From what I remember with my dads 1966 Beeline truck camper. He would lift it slightly off the truck, level it and pull the truck out. I remember him turning those winder jacks 7 turns each and he didn't stop until it was on the wood he used to support it. He gave that camper to me and I have tons of polaroid's but I did it the same way he did on my old F150 3/4 ton. I can't remember but maybe about 2 inches with 7 turns. Too much time has passed. I also remember it was very flexible and stable. I'm glad your project turned out great. Good camping to you....
Joe