Duke,
for what its worth,,
what I typically have done is cover the wing before it goes in the fuse. Most of the work is  done on the fuse as well, covered and doped
Then put the wing in the fuse align and secure.
then Is when I do my fillets, it gives me more strength on the wing being covered first, It also gives you a more stable substrate to create your fillets on.
I then never cover the superfill. Ideally when you are done with it, it wont need anything except a coat of primer...

there are several threads which covered different application ideas, mostly they are subtle differences,, Probably worth spending some time with the search, I think you would find good info as well as any other answers here

Thanks guys.  Do you leave the covering on the wing/fuse joint also? Or raw balsa?

I apply a few coats of dope to the covering to get it tightly bonded to the balsa then apply the Superfil over it. Before it cures shape it to a radius, sand as necessary after it hardens, then prime/paint etc.

James this is the correct method.

Thanks again!