The Finale thing is just a Finale thing... (if you use it regularly, you probably know what I mean. Otherwise, just trust me when I say that, though powerful, it's a bit of a pain in the ass!) It's a way to get the bottom note(s) of a chord to play back a little late, as suggested by Herb above as the proper technique for making use of the "chord-trem". It's also used to make rolled chords play back properly.
I was a drummer for years (still play a little), so playing them on the keyboard is not a problem, but I like to write directly to score, and I prefer the quality of sampled tremolos, if possible -- there's a different quality of attack and sustain... don't know, maybe that's crazy, but using the sampled tremolos also works better with notation programs. And yes, I'm clear on how tremolos are written, though I'm only writing them by their full duration, at this point, to avoid lengthy messing about in Finale (which is never fun!), and in order to get the playback to work properly with the sampled tremolos. And yes, I realize Finale is not *usually* used for playback, but I've been working for the past year on a MaxMSP program to make Finale much more powerful to use with VSL -- in fact, now that I'm getting into the testing stage, I have access to pretty much every sample in both Opus 1 and Solo Strings on a single machine, with only 1.5 GB RAM, and all working from Finale! Pretty cool... for me, at least.
Thanks for the tips, anyway!
J.