RE: Gap between surfaces using robart hinge points
If you have not glued your Robart hinges in yet, I would remove them and cut a small, square cut-out in each side--wing TE and aileron LE--tapered in to the hole, matching the taper on either side of the hinge hub. I use a micro-saw for the vertical cross-grain cuts and just the point of a #11 blade for the horizontal cuts. Actually I make these cuts first, giving me a flat spot to drill into for the hinge holes. A jab with a tapered punch will give you the perfect starting point for your drill bit.
I try to get contact along the entire hinge line between fixed & moving surface (both edges tapered, of course). I use just a drop of aliphatic in each hole, let it run down into the hole, both pieces at the same time, then press them together with the hinges in the middle. A fat drop down the hole will soak into the wood and get pushed to the bottom when you insert the hinge. If the glue is not runny enough to flow down the hole, a short length of pipe cleaner can be used to swab the glue down the hole. Don't use so much glue that it will squeeze out when you press the parts together. When you're glued up, flex the surface a few times to be sure your hinges are properly aligned.
As soon as the pieces have been pressed together, even though you would think the glue is still wet, I have been unable to pull the surfaces apart. So be sure you press the pieces tightly together right away, cuz that glue sets up quicker than you might think. Dry fit once or twice to be sure you're ready for glue.
If you've already glued, then a 1/8" gap will not be a major handicap. You can fly as is and probably notice nothing that bothers you. Or you can seal with monokote or gap-sealing tape for complete peace of mind.