ORIGINAL: alex7403
I’m asking this because I don’t know if what is limiting me is the airplane or me.
Both.
As for Knife Edge, some planes just do them better than others. If your plane won't hold a knife edge, it may be too heavy or need more power or more side surface.
And frankly, both those planes are advanced trainers. You are doing advanced maneuvers. I think it's time to move up to a better plane. maybe something in the way of an Extra 300 or Edge 540.
Get something better, then... Practice practice, practice