"You main problem is the RPC"
Why do you think this is true?
To my understanding, a rotary phase converter makes power just exactly the same way a power plant makes power, by spinning a 3 phase motor. When I got it, I measured the output from each leg. They were balanced with <1% voltage difference between all the phases and had zero reactance between the legs.
What's different about 3 phase power made from a proper RPC?