the 1" arms are the correct ones to use. The side load is minimal. I have over 100 flights now with that setup with not a single issue. I might also add those were very abusive flights. On the control horn tap issue, I put the the 4-40 tap in a drill and just went ahead and tapped them, no need to drill them out.

p.s. Chip Hyde has been very helpful with any and all issues. I don't know where capngriz gets off on saying good luck getting any help! As far as the weight goes, the plane flys great , Capngriz should go fly a scale and give up on airplanes.

Mark