[PxTx]

Typically 4" of 3000psi concrete is a minimum. Some lifts like Mohawk do everything in an overkill kind of way. You probably should see what the lifts you may consider have for recommendations.

That extended angle iron in pita2 could be added to most lift and i probably would. As long as you rest on the locks, i would store a car this way. Check min lock heights.

Cool part is you cheat space a bit cause wheels above can hang below the roof line of the car below.