I'm kind of a perfectionist too, so I know where you're coming from. Seriously though I wouldn't worry about the joint too much. When I pulled mine off the table and removed the wax paper, there was about a 1/8" gap that was filled with epoxy and I had to grind off the excess, being really careful not to touch the balsa sheeting.

Once I was done it was smooth and good to go. After you put the fiberglass cloth on that joint it's not going anywhere.

Not sure if you're up for it, but I finished mine with Sig Koverall and dope. You can't beat a painted finish in my opinion. It turned out great and you don't have to worry about the covering lifting up and fuel soaking the wood.

Let me know if you have any other questions on your build.

Brian