bushing

Hi, I'm a complete noob, so purchased a handful of props to test from Hobbyking, as I wasn't sure what size I would need. I'm building the swappable trainer - NTM 26 28 1200KV motor, 3 cell 2200 battery. Only 2 of the props came with a bushings kit (6x4, 8x4) so I have several props that...