Ride height is a redundant setting in circuit cars it's not something you need to set, just set your droop to the same "down stop" setting as on the standard settings in your car manual.
With the car on the setup blocks wind down the spring collars to just touching the springs, this will then give you the correct ride height for that droop setting, it will allow the car to unload off the spring under braking/acceleration but no more.
There will be an optimum downstop setting for each tyre diameter, experiment with the chassis until you find this and you can stop chasing setup around like a headless chicken and get on with driving.
For instance if you set the droop blocks to 9mm/2mm on a Shepherd Velox V8 and set the springs to touching on the blocks, on tyres of a diameter of 69/76, which are qualifying tyres, you get the perfect ride height and a car that just comes out of spring pre-load under braking/acceleration.
For finals droop settings of 8mm/1mm and springs set to touching gives a good ride height and droop for final diameter tyres.
Simples, never fails, mega consistent and no room for error or tweak.
And if you want to allow the car to unload further on either end you know exactly where your starting point is for that diameter of tyre, obviously tyre wear will allow the car to get lower to the ground but this is a consequence of running foam tyres we have to live with in long finals.