I agree totally with the above, PC curing occurs at between 180-200C, I imagine that Alex's track tyres operate at between 90-100C and the heat from his discs at well over 200C, this heat is directly transferred to wheel. You can even get burnt from letting the hot air out of a race tyre
It is fair to say that you'd be foolish not to ues a reputable company to carry out PC on the wheels of your pride and joy, and by offering that knowledge that's where this forum excels. I persononally use BA wheels in Norwich, the service, finish and expertise this company offers is fantastic, they remain in service because of this.
To say that PC will warp discs is bit of a misnomer, however attention to detail will warp discs. Don't mount discs to an uneven surface why would you?