I mounted ours on the roof. Got a piece of 12" square stainless about 1/4" thick. Drilled 2 holes that met the lug pattern and got grade 8 bolts welded on long enough to fit the rim with nuts.
A bunch of #12 stainless screws around the edge of the plate to hold down. 2 layers of fiberglass cloth slightly larger than the plate to help hold down and seal any chance of water leaks. Extension ladder at an angle easily got it up there. Gravity is your friend getting it down! Tire has a snap on cover so no uv but stays under shelter when not on the road.
