Trying Sarthe at the Moment... my setup:
Lvl 38 Bob
Toyota GT-ONE
Oil change
Mid RPM Turbo
At the end of the first lap, I was 8th.
I pitted at the end of the 2nd lap for Intermediate Tires. 3 others pitted with me. The track "wet meter" was at 16%, thats why I chose to pit.
At the end of the 3rd lap, every other racers pitted so I went into first place.
At the end of the 4th lap: +8.816...
At the end of the 5th lap: +10.804... rear tires at about 75%, 90% for the front ones.
At the end of the 6th lap: +6.154... kind of forgot to watch the pace, Bob was cold as hell (!) rear tires at about 55-60%, front 85+%
At the end of the 7th lap: +15.656... hot paced, tires about the same as those at the end of the last lap. but they do burn down! hah!
At the end of the 8th lap: +18.548... kept my pace at ~55-60%... rear tires almost worn off, maybe 25% left... will try to end the race with these ones...
At the end of the 9th lap: +21.642... accidently skipped pit... i finally ended the race poorly, my Bob had no more strenght, was driving pretty badly. So I should have pitted!
Do what I did, but PIT at the end of the 9th lap, and you'll be totally fine! I pushed my luck too far
Hope this setup helps you!