Don't know if this has been mention on here before but there is a fairly simple solution to this.
Undo the 3 100m nuts. Lift the back of the board and shim it out by a couple of millimetres (between the board and the hanger rear of the top nut). Tighten the nuts, being careful to not over-tighten. Think it heightens the back by about 15mm.
Did this and I didn't scrape the boards once, even though I was riding with a passenger.
BTW. nothing wrong with sticking the pre-load to the top. It doesn't affect the stiffness noticeably, just the ride height.