My races are 20 minutes. Getting the rears to come in quickly is very important, because reversing into the barriers at Quarry (Castle Combe) or disappearing backwards down the escape road at the hairpin (Pembrey) on the first lap is never good!
20 minutes is unlikely to result in any serious issues with overheating at the front (assuming that the set up is good), so I need something that heats up quickly and is working reasonably well within a lap, so 888Rs or Direzzas look like the way to go. I might run 205s on the front and 195s on the back to try and get some balance.