Are you going for rebounds with good timing? Honestly it's easier to crash the boards coming from the wings especially as a SF with decent athleticism.
4.5 Reb per game is not bad for a SF depending on where you usually are on the floor when the shot goes up. If you want more rebounds then you just need to guess the angle of the rebound and go after the ball. Speed and vertical helps a ton. When down low, box out and fight to maintain position.
Side note: what's with all the freakish players people want to make? So many 6'7 point guards and 7' centers...
If you like big men, it would be Wilt Chamberlain. Or if you're racist you're gonna pick Larry Bird - Horry
I have a 6'5 sg and I average 7 rebounds. I think the main thing is boxing people out. Before I started boxing out I would just stand in a good position and when the ball came off the rim I'd jump and then someone behind me would jump into me and get the rebound and my player would slide out the way.