Gary,
Thanks. Sounds like a GREAT set-up and you've really done your homework.
Question: On the FL106 frame with the Class 8 drivetrain, is this still a single-axle 33,000 pound GVW truck (in other words, no 12% FET)?
Just out of curiousity, have you considered the Eaton-Fuller Super-10 box vice the 9 speed? The idea here is to streight lever-shift it like a 5 speed 'till you get in top gear. Once there, when pulling a grade, it's a simple button-shift from 10th to 9th (and back again).
I found, from back in my Class 8 semi-truck days, that shifting a Super-10 was easier than working a standard 9 speed (with the range shift between 5th and 6th). Novice drivers will have an easier time with the Super-10 (my opinion, anyway).
Rams Fan