Well once I get mine started it spins my 11 x 5 pretty fast, especially when I give it a pinch to check the mix. I don't have a tach, but it sounds like no slouch to me.
I probably just need to get some experience with it and let it get broken in well. It had more static compression new than it does now, so that was my biggest worry. But it sounds like static compression isn't going to be very high on this ringed engine anyway because of the gap. At operating temp and high rpm that's not going to be a factor, so I'll just fly it.