No propriety tools. That’s important to us home mechanics. One reason I stopped overhauling dampers at home is that many forks require those tools. A one time purchase is acceptable but when the tool changes from model to model it pisses me off.
I have had forks that needed an air relief because of I think negative pressure in the open bath. Hard hits see an increase in psi in that chamber and hard hits cause maybe some flex and air escapes through the wiper. The results are a fork that is partly sucked down by over a cm on a 150 and 160 Fox 36. A careful insertion of a very small plastic zip tie cures that. It’s not hard to do but care is needed to not damage a stanchion or wiper. A PRV is just easier. Do motorcycles have this issue?