Don't know how to ask/don't know what I want.

An easy way to get smoother steadier lowering is to make a handle at a right angle for the pressure valve. Even if it locks/lowers through the pump handle, one that shoots off to the side will help get a small, controlled valve opening for the right amount of drop. Could be as simple as drilling a hole through the end of the pump handle and putting a piece of bar stock through when you want to lower it.