Sounds like a cracking day out! I'm itching to get to Curborough for one of these sprint days sometime, seems like the ability to time really adds something.
I must pull you up on this though:
No, just no
Oh, and NS2Rs are pretty much bang on the same pace as the Federal RSR 595s, I've tested them back to back (both are control tyres for our series). Both are fastest when they are nearly worn out, too.