The mod does what it does by limiting valve dwell and lift, so it works best when tuning down a gun that is capable of much more power. .
I reversed the simplest of rules: its the SQUEEKY wheel that needs the grease.Without the o-ring mod, was getting an efficeny of about 11.6 bar-cc/fpe (or about 1.4 fpe/cuin). Changing something as major as the dwell/stroke in isolation was not a wise idea.
Hard to say. Sounds like a good experiment. My guess would be harder would give a flatter shorter string. Softer would be longer but more ES. But in an airhog of a .25, probably not a noticeable difference either way.I've always just used 70 duro.