You either have a Ford truck or a really old TC. Fords have tall cabs, and old TCs were made when all trucks had low cabs…
I use a super cheap floor mat rubber, probably made from old car tires. All the mat does is keep the TC from sliding around on the slippery metal bed. The horse mats are ideal as they are thick and you should get much less slide than a thin mat.
Look up on theTC forum about supporting the camper when it is off. Many use an "X" support made from one piece of plywood. How to make will be in many post, and the pic tells it all, but you put that 3/4 inch plywood, now 4 pieces of plywood, laying flat under the TC when on the truck, so take it with you. you get 3/4 inch extra height, and you have a base stand with you at all times just in case.
You still need a rubber mat, so that is extra height even.
HD can cut the wood in 4 pieces for you but I doubt they can make the cut that makes it work into an X.
Basically you cut a slot half way through each piece so the two halves can slide together making an X.
Im having trouble searching for it, so you may have to browse down the TC list.
On mine, I put the rubber mat on the truck bed, the wood on that, and the TC on the wood, then I used that foam-like rubber floor mat on top of the wood to keep camper from sliding on the wood (since mine is a fiberglass belly).