I just pulled my woefully unbalance GP spinner from my Christen Eagle II and replaced it with the Dave Brown Vortech. I had to enlarge the prop holes a little but I can now idle my Fuji BT-50SA and actually see the nose of the spinner. My only complaint is the spinner bold was not long enough. I temporarily solved this by using a 10x32 blind nut as a coupler to connect additional thread -- its working fine; maybe I don't need to replace it.