In the second email from Airtronics they confirmed that the SD-10GS uses a different gimbal design. They also said that the trade-in price would be $279 (down from the $399 list price so that's pretty good). I don't know if I'd just bring in the busted Tx or whether they'd want the entire "package" of Tx, Rx, batteries, etc. I assume just the Tx.

Unfortunately, they don't accept direct customer drop-offs at their repair facility (in Fountain Valley, CA). But told me that I could put in a repair request at the Fountain Valley Hobby People store (which is just around the corner). That's fine if they could get the work done in time. I'll only be in the US from March 16 to March 31. I suppose I could ship it from here (which would probably cost $20-30 bucks) and they could ship it back to my SoCal address.

As far as how the repair was done, I doubt very much if they change to a different wire. They probably just add a bit more slack and maybe the globs of hot glue (if that wasn't already there).

I have managed to transfer all of the failed RDS8000 settings to my other, still functional, RDS8000. So at least I can fly my ARF until March. I think I'll hold off on flying either of my WWI scale models until I determine what I'm going to do about a new or repaired Tx.