For example I would use losi red piston with oil30. Even with the 1.1mm holes pistons from tamiya, with oil 30, it still feels softer. So if I want the feel and pack as losi red pistons, there is no way to do that with tamiya pistons. (in yokomo shocks!!)
Less pack is good, if you want less pack of course
But that's not my point. I just want a decent set of pistons for yokomo shocks (cause it doesn't exist), and tamiya pistons are not usable for that. Maybe kyosho pistons are, because they seem to have the same outer diameter.
(losi pistons don't work as their shaft diameter are bigger, so they sit loose on the yokomo shaft)