For ride height, I use a metal ruler what has the measurement indicators from the edge of the ruler. Yes, very old school. I know they sell gauges for ride height that look like ramps, but as Granpa mentioned the actual height is not that important to me either.

It's the difference between the front and rear heights (rake) that is important. Honestly for these m-chassis, I try to maximize ground clearance. Like that SabreFD Mini I was working on, 10mm clearance from bench top to bottom of lower CF deck. I need this level of clearance when I'm driving these cars out on the parking lot. If this was a real car that's still 10-12cm.. that is pretty low slung.