I have 3 packs of these:
Amazon.com: Tri-Lynx 00015 Lynx Levelers, (Pack of 10): Automotive
Yes I use 15 on each side, and yes I have someone stand next to the camper and spot to let me know when to stop.
It raises the front about 6" or so. I wouldn't want to go any higher LOL.
I build a ramp with them, lets see if I can remember the sequence: (Top to bottom)
Each layer overlaps the layer below it by 1/2 (remember playing with Lego
). There is only a ramp on the road side (I'd need more to have a ramp on both sides).