RancherPete, where are you? For some thing I read in the past, I think you are in Colorado, like me. The reason I ask is because of similar altitudes. I'm at 6840'. I fly an S800, Zenmuse, 8000 battery so I'm definitely heavier then you. I think I'm at 12 pounds. Like you, I have implemented Denny's hubs and the APC's. Definitely better on vibes and jello but definitely worse on lift. Takes more RPM to keep it in the air along with less throttle response. I had a prop stop spinning (I figured out that problem) and at full throttle it's attitude was great but not enough lift to come down slowly. The whole thing grenaded. Are you getting plenty of lift with the APC's at your altitude compared to the stock CF's? Also, I think you are the one that started the specific silicon caulking technique between your reinforcement tube and the arms. I tried different techniques, for me yours is the easiest and most effective out there other than massive amounts of work. I break arms so it doesn't make sense to me to do all that reinforcement work and then just have the arm snap at the hub connection. I thank you for that tip.