A slight depression is all that is needed, just enough to separate the clutch from contacting the plate. As Tx Jim said, I don't think total depression would weaken the spring. Besides, the strength of clutch mashing against the plate is probably why they stick together While sitting (and maybe rust). He can watch thru the inspection hole and see how much depression is needed for separation. It's just easier to apply the stick by using the slight pressure. Can even be done by hand after you dismount.