That would be me, and, since most of the jazz tonalities of the 20th+ Century are built on French Impressionists' work over 100 years ago, probably you should too - if you aren't already (and I apologize in advance if you are, and your crack is, well, uh, tekminus as usual).
As I've mentioned on this forum, I did my work exactly as you describe, using Noteworthy Composer. Manuscripting is also the only way I can write, but there's no question that some things simply won't yield to MIDI. You're lucky to have real live people to play your music.
My MIDI work ended up happening because it was the only way my stuff was going to get recorded the way I heard it - not to mention the fear that, although not much, what chops I had would be gone before I dragged a sufficient number of geezers into the studio to do the deed. By the way, I posted 64kb MP3's of most of my last CD on my educational website at http://itech.fcps.net/trt15/Sound/MIDI/JLJ_Originals.htm
, if you want a listen. Styles range from pop to country to jazz, but I won't pretend to have your guitar skills. Try to make up with it through some second-tenor vocals, some attention to arranging details, and (of course) stellar good looks.
Like you, I multi-tracked the recording after the sequences were down - I used a rented Alesis ADAT for that.
I moved to Cubase and VST synths as a way to gain more control and realism (especially over tempo and traditional instrument sounds), as well as providing the multi-track recording "in-house." But the learning curve has been too steep, and a newly-started college degree program (lending yet another ironic twist to the "OldSchool" moniker) too time-consuming - the stuff is just sitting there.
Any-hoo . . . enough about me. Add me to the list of the folks wanting a CD copy when it's out.