You have a pretty good idea on which to do and not to. If it were me I'd use an 8.5 geared to manual specs. Stock timing aka 30* or so, then blinky esc settings aka no timing at all. Then go out on the track and get my slipper broken in if it's new or freshly assembled after being cleaned. Then gear till my car topped out about 10-15 feet before I let off or hit the brakes at the end of the longest straight. After you get the gear sorted out your temps should really be in the 110-145* range. Just take it slow after you get the gear figured out roughly, every min or so check temps. Or have someone check for you. Fans really aren't needed in mod buggy, if you need one something is up with the drivetrain or timing is too high, possibly over geared as well. Keep your motor under 165* and it will live a long time.