Ride height depends alot on whether or not the track is smooth. On my track, 4-5 mm seems to be norm, just because of the bumpy carpet.
Most smooth tracks run a 3mm minimum, but with wear in a main, you might want to go 3.25 or 3.5, depending how fast of motor you're running and what tire compound you picked.
When you're setting ride height, it is best for the chassis to be level, but once the height it set, then you do your droop setting via the center monoshock.
Also when you check ride height check the pod and the front of the main chassis.
RC America|EA Motorsports|ORCA
WCICS Rep - Round 1, Saskatoon, SK