Scot I set up the two small balsa formers over the plans and tacked them to the 1/4" dowels, then placed the ply formers in place and looked down the center of them. They need very little adjustment on right boom but had to re-drill the holes for the dowels in the left boom. They were off 1/16 inch, doesn’t sound like much until I looked down the center and noticed that if I did adjust them the rudder would hit one side on full travel. Like you said best to line them up by eye. I am also working on getting the right and left side extensions to be at the same points on the boom where the leading edge and trailing edges end, all I am doing here is getting base measurements and try to get them the same on each boom.

Ron