Forming a wing joiner isn't the problem. Removing the original joiner is the problem. It is well epoxied in and can't be removed. Afraid trying to drill it out will only result in "slipping" onto the balsa wood and destroying it.

I'm comtemplating rebuilding the wing with no dihedral anyhow.

And should the fiberglass run from trailing edge around leading edge and back to trailing edge or will just a strip on top and on bottom suffice. If I make it run aroud the leading and trailing edges, it will no longer fit in the wind saddle of the fuse.