I gear real close to a rollout of 40 or 41 for stock with a P2K2. Monster will like about the same or a little lower. You will get many opinions. This is on a smooth carpte road course 100 X 40 or like that.
Yes adjust your ride height as the tires wear. You will get the hang of it, the thing I needed and still need is time on the track.
Ride height at my track is a minimum of 1/8 and I stay close to that.
I always use a 100 or 98 spur. Pinions in the low twenties to thirty will suit you well.
All My opinion
Have fun
David Root