I would use those inexpensive jacks that Camping World sales! I see a lot of them at RV Parks being used by RVers with travel trailers. They put all 4 jacks in each corner of there coach (on the very outside corner to where you don't have to get under the coach. Way back in the day I owned a Class C without levers and that's what I did to stable the coach. I went to Lowes and bought 1 - 2" X 10" X 8' Douglas Fir Board, Lowes makes 3 cuts for free so there's your 4 pieces wood to put under the jacks to spread the weight distribution. When it starts to get hard to turn that "turn screw" on the jack by hand thats all the pressure you need worked for me many years.