I finished drilling the spar and then deburred all the holes.
I then spent the next hour or so setting up to do the next batch of priming on the parts, which involved the eko clean, eko etch and prime in green. A couple of light coats and it has turned out quite nice. I did lay the last coat on a bit to heavy, and could do with a decent paint filter and decanting equipment to get a better consistency in the paint.
I also spent 15-20 minutes coming up with a rough practice strip of aluminium to give the hand squeezer and a 3x rivet gun a go. Hopefully I can get most of the bad bugs out before I start riveting the practice kit together.