Hey Coolair! I have two packs but I like the performance the best with my 1500 mah 3C electrifly pack. I am also using a Hacker 20-20L with APC 10X4.7. All up weight according to my mail scale is 17 oz with pack. This by far offers the best performance. Now I have a 2100 mah electrifly pack as well. I can definitely tell the difference. It requires a little more effort to hover. This may be partially because I am a little more nose heavy with that pack. My center of gravity is 4.25 inches back from the leading edge. That is 1.25 inches more that the recommended starting point. I run alot of expo on the elevator. Just checked and I am at 53% on the elevator, 40% on the ailerons and I run no expo on the rudder. I like an extremely sensitive rudder. I'll see if I can post some pics this weekend of my set up. (Also the plans show putting the rudder and elevator servos right after the wing. I put my down right before the horizontal stab and have about a 3 inch pushrod driving the control surfaces. I did not have to add any weight to the tail to balance out like I have had to do with other foamies. I hope this helps you out. Talk soon!