I'm using 4131's, four of them and just standard 15.00 servos on the rudders. I went with a 4131 on the nose steering as I really like to have steering authority. That puts me at about 180 onces of torque on each side, that's a bit more than the 155 ounces of the 8411's they are using on single servo per side on previous versions of the roo. Is your's the composite version or the earlier?