I am flying one now with the zenoah 80 twin I have got the balance set at 2" behind the tube, and the weight comes in at 23 lbs. It seems to fly great. I also have the 1/3 cap, it is alot more agile in the air however the sukoi is alot more rock solid in the air. I am going to build another with the zdz just to go crazy with, and then decide wich I like better. If you want to fly mine shoot me an e-mail as I live about 3 miles from you and would be glad to let you take it up.