Copyist's Helper is a tool for professional copyists, especially those who work in the New York theatre market. Its purpose is to make as effortless as possible the creation and revision of measure numbers and staff name (and instrument name) headers. In most cases, these are accomplished with a single click.
Some recommendations for how to use the plugin appear below.
You can download the latest version of the plugin here. If you have not registered, you can try it 30 days for free.
You can register your copy of the plugin here.
The placement of measure numbers is extremely important for music in theatres and other venues where rehearsal time as at a premium. Copyists (and their supervisors) have developed placement rules that maximize the efficiency of the rehearsal process. These rules have until now required laborious manual insertion and positioning of measure numbers in Finale.

Not pictured is the situation where a part (such as a keyboard part) has multiple staves. In this situation, non-boxed measure numbers are positioned above the top staff, except for multi-measure rest ranges, which stay centered and below. If the part varies between single and multiple staves, the single rules apply for the single-staff systems.
The plugin also handles the situation where measures have been inserted or deleted. In this case, copyists create multiple non-overlapping measure number ranges to maintain numbering consistency with the original version. (They also lock all systems, so that boxed number remain at the system left edge even after inserts or deletes.) Inserted ranges have numbers like "22a" thru "22d". After inserting or deleting, and creating the appropriate measure number ranges, you can re-run the plugin, and it recalculates all the measure number placements, including the boxed numbers you specify.
For the plugin to work, you must first create at least one measure number range with the following attributes.

Numbers With Enclosures
List. List every measure number that should have an enclosure, separated by commas. Enter measure numbers the same way you would in Finale's Scroll View. There is no set limit to how many numbers you can enter here. (They may scroll beyond the end of the visible area in the edit box.) For a very long list, you may find it easier to paste the list in from a word processor document.
Position H V. The placement for boxed numbers. A horizontal offset of 18 evpus left-justifies Finale's default enclosure, so the plugin defaults to 18 evpus.
Place Enclosed Numbers on Top Staff Only. Checking this option causes the listed numbers to be placed on only the top staff. If measure numbers would not otherwise appear on the top staff, the plugin uses text expressions instead. When this option is unchecked, enclosed numbers are placed on any staff where measure numbers appear (based on the staff's "Items to Display" and the "Always Display..." options in the measure number region).
Use Expressions for All Enclosed Numbers. Checking this option forces all boxed numbers to be text expressions. Unchecking it allows any enclosed number that can to be a forced measure number instead.
Alternate Font: [Font...]. This option is only applicable when forcing all enclosed numbers to text expressions. It allows you to supply an alternate font and style for the text expressions. Otherwise, they have the same font and style as the measure numbers.
Numbers Without Enclosures
Position H V. The placement for non-boxed numbers.
Vertical Offset for Top Staff on Multi-Staff Systems. Checking this option causes the plugin to use the alternate vertical placement value when there are multiple staves in a system. Do not use this option until you have already extracted the parts.
Center Ranges Under Multimeasure Rests. Turn on this option to center ranges under multimeasure rests. To use this option, the source measure number range(s) in Finale must have the "Show Measure Ranges on Multimeasure Rests" option checked.
Another way that copyists streamline rehearsals is to continually remind doubling players of the current instrument. Doubling parts typically have a staff name that identifies the role of the player, like "Reed 1". Then each instrument has a staff style with its instrument name (like "Flute" or "Clarinet" or "Alto Sax.") that overrides the staff name when the player is to play that instrument.
To remind the player of the current instrument, each page has a header at the top, something like
REED 1[Flute]
Currently, the only way to do this is to manually create a page header for each page. This approach is both laborious and error-prone. Copyist's Helper can do it automatically at the click of a button. What the plugin does is substitute for user-defined placeholders in page headers. To use the plugin, a copyist first creates one or more page headers in each part, something like
$$$Staffname[$$$Instname]
This header can have any font or placement attributes the copyist needs. It can also be global (i.e., on every page or all but page one, etc.) The plugin searches all page headers for the placeholders and substitutes the staff name and/or the current instrument name as specified. Even though a source header may be global, if the current instrument name is different on different pages, the plugin creates as many different headers, assigned to the correct pages, as needed to accommodate changes in the instrument name. For documents with multiple staves, the staff name is taken from the first group name that spans the entire scroll view staves. If none is found, the plugin uses the topmost staff in scroll view. The instrument name is taken from the topmost staff of the first system on the page.
Copyist Helper can also search and replace the current instrument name's placeholder in group names of optimized systems. This is perhaps most useful when preparing a score where, for example, a keyboard part switches between multiple instruments such as Piano, Celesta, and Synthesizer. You could put the instrument name placeholder in the Scroll View version of the group name. Then, after optimizing, you could run the plugin, and the correct full or abbreviated names would appear on each system. This mimics what Finale does automatically with staff names on individual staves.

Replace [...] with Staff Name [x] All Caps.
Replace [...] with Current Instrument Name [x] All Caps.
Use these options to specify the placeholders for staff name and current instrument name. (If you do not use staff styles to override the staff name, then staff name and current instrument name are essentially always the same.) Checking All Caps causes the plugin to convert the name to uppercase when it substitutes it into the page header(s). Leaving a placeholder blank disables the replacement for that name.
Search Page Headers. Enables the page header searching function.
Turn Off "Show Only On Screen" Option. Page headers that contain placeholders are likely to be rather unsightly, so you may not wish for them to print out until after you have run the plugin. Checking this option allows you to have source headers (containing placeholders) that do not print while having resulting headers with the correct staff and instrument names that do print.
Make Copies Rather Than Replacing. You will almost certainly use this option only in conjunction with the previous one. If you check this option, the plugin leaves the source header(s) in place. Leaving them in place makes for easier subsequent revisions, but it also makes a confusing mess on the screen. If you set your source header(s) not to print, and if you also check the previous option, then the printout will be fine, despite the mess on screen.
Search Optimized Group Names (Current Instruments Only). Enables the group names searching function. This function ignores the staff name placeholder, but it uses both the current instrument name and the strip instrument name placeholders. When a group name is found, placeholders in the full name are replaced with the current instrument's full name. Placeholders found in the abbreviated name are replaced with the current instrument's abbreviated name. The current instrument is taken from the top staff of the group on that system.
Other Options

Show All Alerts and Questions. If you have checked any Do Not Show Again options on message boxes or question boxes, clicking this button resets them so they will show again.
Register... If you have registered Copyist Helper, click this button to enter your registration code.
{ Process All Tabs On Go | Process Current Tab On Go }. If you select Process Current Tab On Go, then only the current tab is processed. For example, if you current tab were Instrument Headers, then when you pressed go, no measure numbers would be changed.
Process All Open Documents. This option is visible on in Finale 2003 or higher. If it is checked, then all open documents are processed when you hit Go. If it is unchecked, then only the current document is processed.
Close On Go. Checking this option causes the window to close when you hit Go.
Save Settings... brings up the Save Settings dialog.