Wheel cribs and race ramps suggestions

Cardboard fan, easy to slide on and absorbs any fluids I might spill or leaks. Family now saves heavy cardboard for me.

I'm thinking that 10-14 inch is a good height.

I have about 10-11” has worked well for me. Maybe a hair short. Changed rear seal, clutch, trans, but with trans I couldn’t get the trans out on trans jack. So I slid trans off jack under car then I was able to slide it out from under car.