The 275/315-17 Kumho V710 is the hot set up. We run 10s on front and 11s on rear. The car is perfectly balanced. I tried the 315s all around with the V710, but the car oversteers too much about half way thru the race and it just gets worse. The 275s on front make it more consistent throughout.
I have been running 315/35-17 Kumho's on the 17x10 front and 17x11 rear for two races now (both Mid-Ohio) and didn't experience rear tire fade as you noted. But, I seriously debated trying the 275s front again for lower rolling resistance and aero drag on the fast tracks.
Sounds like you need to stop using that right foot of yours so much. :lol:
All of us T1 guys use 17x10 front and 17x11 rear as we are required to by SCCA T1 rules. That may not be the optimum setup, but there are a lot of tire choices available for these wheels.