I ahve built it, and though I'm not as wise as Wayne, I do have some tips for it.
Make SURE the engine area is lined up, or it'll just scew everything. Mine was perfect, and the left wing is a little off, though the pain took care of it. I guess you know the flaps thing already, so that's it! Oh, and don't put the DF loop on too early like I did hehe.
EDIT: That came with Romm's?! I love that scheme. I'd do that one actually, though if you're set on either ret 1 or 13, do 1 of Dortnmann's.