RE: plane balancer
I built a sling i hang from my cieling. I took a piece of angle aluminium but you could use a yardstick and place two loops hanging from the ends and place a plumbob in the center then hang the whole thing from the cieling. Place the wings in the loops and the plumbob points to the cg. one thing i have found is tie a knot just under where you attatch the loops to the rod. this hangs the plane from two points and is much more accurate. It is cheap and works really good