bojangle

The parts fit on modern kits is so good that the basic structure of a wing can be assembled first, then CA applied. In fact, some manuals have large warnings "Don't glue until we tell you to". This is so you won't end up with a warped wing, or they intend for you to jig in washout before gluing. Wing and deck planking have also been eliminated in many kits.

Whether kit or scratch, if built carefully there should be no gaps. I use epoxy on all formers, firewalls and ply braces.

If you plan to have planking on the decks or wing, then you need aliphatic. But there is a trick that the directions don't mention. You must "double glue" all balsa parts. Just applying once to both surfaces and joining isn't sufficient. Planking needs to be pre-formed/fit and dry before gluing. Aliphatic doesn't wick into joints, so applying after tacking with ca doesn't serve much purpose except to add weight. Adding additional beads of glue on top of the joint is like pouring oil on the outside of your car engine.

Aliphatic is good for laminations, but you have to clamp immediately as it bows the wood.
If you perforate or cut lightening holes in the laminations, then you can use CA. My fuse doublers look like swiss cheese. Once I weighed all the cutouts, over an ounce saved. On a light plane, that amounts to a 20% reduction in weight. I recently built a 25 size Kaos type, total airframe weight was only 20 ounces.

For the average 40 size plane, the total glue used will be about 1 ounce more or less, and more isn't always better. From the looks of some ARFs I've seen, I think they pre-assemble the entire plane, then dunk it in a vat of glue.

BO