How do you determine "ride height" to make suspension mods??

Take that last picture and drop her 2-3 inches

If I do that the frame will be a bit too close to the ground for the hilly roads of western PA.... The 3rd picture gives me 5.5" of ground clearance at the torsion bars and 7" of ground clearance at the rear front spring frame rails...

Dropping the 3rd picture by 2-3 inches might be too much... surprisingly enough the front at 24.5" is only .5" higher than the G-force Demon.