MSC 22-8 on the 3.2 will turn about 6,900 rpm but out pull most any other prop at a higher rpm. It's a wide blade thing.

A Menz 22-8 will turn in around 7050-7150 and a Mejzlik will get in the 7150 to 7250 rpm range. The MSC still out pulls them. Forget the Zinger. In testing and actual flight it provided the highest rpm numbers but the worst flight performance.

I've flown a Brison 3.2 in aerobatic planes up to about 21 pounds and it did quite well when heavy. Not a hovering engine at that weight but at 18 pounds does just fine. A little slow on the vertical pull out of a hover but that's to be expected at 18 pounds and up.