That does sounds like a hassle. The AMC/Laycock system has a simple system of switches.

There is the Master Switch (on the turn signal stalk), a throttle switch that disengages the OD at full throttle apply, a 3rd gear lockout switch that only allows the OD to engage while in third. Going full throttle or downshifting to second automatically disengages OD. Lastly, there's a centrifugal speed sensor that is inline with the speedo cable. It will allow OD above 37 mph, but disengages below 32 mph.

I suppose with an automatic, one could wire in a kickdown switch. I'm surprised GV units don't come with the centrifugal monitor.