We love our Oregon Aero seat for the -3, but be aware it isn’t light either. Doesn;t make a difference for us with our constant speed prop - the airplane goes like a scalded feline, both horizontally and vertically. We had to send the bare foam back twice before covering for them to get it right - they did have a cut-out for a manual flap lever initially, but I think it might have been on the wrong side. We had them remove that, and open up the stick space a little, and then cover it - still the most comfortable seat we have in any of the planes.
Ours was made over a decade ago now, so who knows if they still have the pattern...call and ask!
Paul