The only real difference between the 4" & 3.5" handles is that the 4" handles are better suited for wood control panels. You could get away with the 3.5" handles in a wood control panel, but even after routing out for a 3/8" mounting depth they will probably be a bit on the stubby side, kinda like a Pac-Man stick. Performance-wise, I don't think there is much difference... unless the short 3.5" stick feels uncomfortable to you, then that may hamper your action on it. Personally, I wouldn't use the 3.5" sticks for a wood control panel on a multi-purpose cabinet where you will be playing a variety of different games.