When you buy Finale, you get a comprehensive range of instruments – Orchestral, Jazz, Ethnic, Synthy, etc.
Many of these are ‘cut down’ versions of full Garritan products. The Violins don’t have all the keyswitches that are available in Garritan Personal Orchestra; the Brass and Saxes don’t have all the controls found in Garritan’s Jazz and Big Band (JABB) or Concert and Marching Band products.
The idea is that it’s enough for basic use, but if you want more, you can buy the full products.
Now, John Barron has made a set of Expression Maps and a Playback Template which is designed to be used with the instruments in the purchased JABB package, not the Jazz instruments in GIFF (“Garritan Instruments for Finale”).
It’s perfectly possible to make expression maps and a playback template for the instruments that are bundled with Finale; but no one has done that yet.
However, you may find that these expression maps work a bit better with the GIFF instruments, though you’ll be lacking some functionality which GIFF just doesn’t have compared to JABB.
JABB Revised.doricolib.zip (3.2 KB)
However, before you buy any Garritan products, bear in mind that they haven’t been updated in years, and are likely as dead as Finale. (“Latest News” on the Garritan home page is dated 2019.)
You may find the following discussion about other Big Band libraries of interest.