Ray - The lack of air gap and hard inserts are killing you. Back in the day before foams took over in the US we would run Sorex 28R fronts and 24R rears with Yok firm thin inserts. That would yeild tons of air gap and a very fast tire. However...it would only be good for ~3 runs before the rubber got so tacky the car would start rolling over.
I would say Take Off RP30GL front and rear would be better. They have good air gap, the rubber is more acted upon by Paragon GFX so the traction is really good but they dont seem to have the built up tackyness problem of Sorex and Pit tires.