Elwood,
Look at the side view of the fuselage on the plans........gives you a good idea. Make them longer than the opening you cut for the servo so the front hardwood strip can be glued to the main spar and the sheeting and the back strip will be glued up against the sheeting. I'll measure the size of the hard wood strips and let you know.........they worked perfect on my first one. I'm on my second 4 Star 40 right now. The first one was great...........This one is a breeze. I'll have a Saito 56 on mine to. JT