ORIGINAL: the-plumber
ORIGINAL: mulligan
What's wrong with simply using a straight edge to get nice edges on each piece and gluing together with wood glue? A doubler isn't needed.
That works for skins, but using a plain butt joint in a fuse side isn't a really good idea. Butt joints (as in skins) are the weakest of all joints, and fuse sides have to tolerate stresses much higher than the stresses imposed on skins.
$0.02
Thanks for catching me, plumber- I missed that part of the question, and didn't realize this was the structural member of the fuselage.