quote:will they be adjustable sitting down in the pan?
No in any true sense.
You are dropping the seats down a couple of inches into a pit. The seats normally only sit an inch or so above the floor.
Once in the pit, their adjustment will be only to the edge of the pit.
Most of us are the only drivers of our cars. The seat position is for us, and once set doesn't need to be changed.
If a future owner has shorter legs and needs to slide the seat forward I imagine they could build seat track risers to solve the problem.