2 post lifts

I’m getting a 24x36’ 6” thick concrete slab poured in my yard soon that I plan on eventually putting a 2 post lift in the center of, and maybe one day putting a roof over. After doing some research I’m starting to think it might be a good idea to get the center area of the slab poured thicker for safety reasons.
What thicknesses do y’all have for your lifts? And how far does the extra thick areas go out past the lift? I know every lift manufacturer probably has different rules for their concrete, but I don’t know which lift I’m getting yet because I basically know nothing about any of them. I just don’t want to have to go back and cut up a fresh slab to thicken the concrete.
What’s a good “affordable” lift?