[tomtom]

8.5T is quite enough, 7.5 is a bit hot, not much but can increase mistakes (and I use to run 7.5, now 8.5).
7.5 is a bit more fun as you got speed but most of the time you'll be quicker overall maybe even lap times with a lower turn.

6.5 is way too much unless you're Houdini behind the wheel, even more mistake and breakage at some point for sure.

2wd -> slow is fast, no need to overpower every corners.