For leveling I use plywood, I made the pieces large enough that the whole tire fits on the wood just as it would if it were on the ground. I have three pieces, two are screwed together (1/2 inch plywood), and one is separate. This allows me to have three heights (1/2, 1, and 1 1/2 inches). Where I store my camper I must use all three to get the TT level side-to-side, I have electric where I store it so I keep the fridge on all the time which must be leveled. The "lego" blocks I use under the four corner leveling jacks.
