So i think my next portion of the bmw project will be...

the rotisserie locks with friction, which is scary. (bolt presses into the tube)

I may or may not have a lock. It depends on the valving

simply use cylinders with a PO check in them. If the valving is at the cylinder, as long as the cylinder is not going to be removed while the car is raised, there is no REAL need for a positive lock.

however, if the valving is at the pump, you need a positive lock for safety in the event of line failure.

I would probably put one in just because it was easy. but with PO checks in the cylinder it would be pointless.