Cycling the compressor and/or the cond fan is a good call. In fact, I'd rig up a switch to cut off the compressor based on throttle position as well. Full throttle equals no compressor!
But, I'd like to keep the whole wiring scenario simple. Thus, I'd rely on the T-Valve to control temp and the pressure switchs for protection. Even if the T-Valve is at minimum flow you sure could freeze up the Evap, especially if it's in the recirculate air flow mode. But, thats typical of most all cars. When I'm in recirculate air mode I never run my evap fan at minimum speed, all though it's easy to forget.
My understanding, by the way, is that the GT-40 A/C systems just barely offer enough cooling anyway. Perhaps in a cool weather condition the car might get "cold".
