A good morning walk/work out clears the head. First - I can't believe I missed it and second - how stupid was that?
Third - the fix.
I'll run the ACC2 on the RX to the "throttle in" for the DB3/TBS etc. On the TX, I'll modify the endpoints on a three way rocker switch where UP is Fire Cannon, MIDDLE is neutral, and DOWN is Machinge gun. When I flip switch up, cannon fires and down, machine gun fires. Ceneter position neutral.
I'll then run the THROTTLE on the RX straight to the servo that is connected to the gun elevation.

Do you see any problems with this setup and the DB3/TBS?

If it will work, it absolutely TRUMPS the Clarke board (for me) as the cam style elevation ruins the thrill of the shot. Perhaps, because I've been an active bird hunter in my youth and enjoy target practice to this day, I equate the proper aiming of a weapon with firing that weapon. The cam style elevation is like jumping on the Merry Go Round and waiting for it to go round and round and hope it ends up with where you want to shoot.

With this setup (full elevation control, proper recoil, programmable sound and with the optional amplifier to really get things rocking) and the price drop on the DB3, this would be the system of choice for me. It does require a programmable TX (which I like as I just switch which model I'm controlling - I have 20 model memory function including helicopters). It will also allow one complete unit that can easily be switched between models and reprogrammed quickly.

Now if the TBS has a memory module like my TX where you could simply switch the model sound - that would seal the deal.

Thanks,
tjs