Today I worked on the wings.
I cut small lightening holes into the ribs for strength and to allow snaking wires, tubes, etc through them. For example, I am planning to have working navigation lights on the wingtips.
I placed the ribs (except #5 which will be modified for hinges) onto the spars and glued them using Titebond II Premium Wood Glue. I placed weights onto the spars to ensure the pieces are pressed firmly together.

Tip:
I use a scrap piece of metal torque rod and dip it into a glob of glue then apply the glue using the rod. This enables me to place just a drop or two of glue exactly where I need it. After pressing the pieces together, I use a small flat piece of scrap balsa to wipe off any glue that may have seeped out. When finished gluing, the rod is wiped clean and ready for use again.
I also use this method for mixing and applying epoxy.

Mistake I made:
The lower spar rises to meet the last outboard rib to help form the wingtip shape. To make this bend, you need to cut out a small amount of balsa in the spar just past rib #14. I cut out too large of a piece on the spar and it broke when I tried to bend it. (Shown in the last picture).

Corrective Action:
I decided to use 30 min. epoxy to repair it (instead of using wood glue) in case I jeopardized its strength. I applied the epoxy all around the spar.