Do not let wheelspin on gravel determine how to set your WDH.
The amount of "rise" is also not the correct metric.
You need to measure the front and rear wheelwell height before attaching the trailer (dimension "A" and "B").
After attaching trailer and engaging the WDH, the front wheelwell height "A" should have returned to it's original height. Dimension "B" should be no greater than it's original height, and most likely less. The trailer should be level.
If you do not have these 3 things correct, make adjustments per the Equal-I-zer instructions.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller