Use a potentiometer in place of a 4 position rotary switch?
Yeah, so this post of mine is very dead - and I hate to ressurect it except for the fix I opted for. It's nearly fall again, so it's been a while since I messed with it, but if I recall properly, I used a 20 amp circuit breaker like a toggle switch since I didn't have any other AC switches. The heater originally had, like I said, an off/high/med/low switch, and a potentiometer/rheostat/whatever for more fine tuning. I just wired the heater together as "High" and then to the circuit breaker. It was something like 1 wire was low, 2 was med, and all the hots wired together was high. (As I'm reading what I'm saying, 20 amps seems awfully high, but I guess since it plugs into the wall, it actually has another breaker associated with it.) Anyway, this wizardry surprised the heck out of me that it actually worked and I think I actually learned something that day.  Thanks again to my absolute favorite Stack Exchange community.