I have used lots of 1 1/2" spinners for .049 engines, made by Goldburg and others. The biggest problem I can see is that a spinner that big on a 5" to 6" prop cuts down on the thrust and forward speed. As far as for the larger center hole in the spinner that has never been a problem for me. I will some times cut a small slice of fuel line tubing; I slip it over the screw or shaft and when it is tightened it takes up the slack in the opening.