i used a hall effect pedal assembly (HEPA) from a Prius. It's a common throttle solution for EVs. It has two independent hall signals with slightly different voltage curves. I just hooked one up to the Soliton1 and calibrated the min and max throttle values, shut it down, and then did the same for the Curtis AC system. When they are both on they get the same throttle command but are electrically separated. Therefore if one system is shut down it doesn't effect the other.
I don't have many road miles on it yet so I'm not sure about the optimal driving strategy. I built it more for truck stuff, moving heavy stuff, pulling other vehicles, etc where efficiency isn't a huge consideration as it is short duration work.
The AC motor is undersized for much acceleration, but perfect for maintaining an efficient cruise once the bigger DC motor has done the grunt work of getting 3000 pounds started from 0 rpm. If you weren't in a hurry at all you can not even switch the DC system on. I'll have more data from the two systems once I get more instrumentation hooked-up and working.