I've built 2 of these and the way I finally got it to balance was by using the minimal amount of weight as far back as possible. There is a former located just forward of the stab. I cut a small hole in the covering, then cut a small hole in the fuse. I bought a package of the stick weights with the foam tape and epoxied it to the inside of the fuse straddling the hole. I used a piece of string to pull it tight against the hole. When the glue dried I patched ofer the hole with lightweight spackle and put a white monokote patch over the hole. The fix is nearly invisible and the weight is protected inside so I don't have to worry about it falling off.