The answer to the Sorgum and epoxy / glass finish is, it is OK to do. That was a very popular method in the 70's the skins on my Phoenix built in the mid 70's is still tight no lifting of the skins at all. I have a Curare built but not finished in 1977, skinned with Sorgum / 1/16 balsa and 3/4oz glass cloth with epoxy, the plane has been sitting on the shelf since and the wing and stabs are in perfect condition.

BTW, nice build you have going thanks for sharing!