Rather than spot prime as suggested by Vans, I couldn’t face over 1000 holes! I decided to prime the top of the spar flanges … although a bit of work setting up to spray etc, in the long run I reckon it was a bit quicker. Also, I found a few places along the flange edges that hadn’t been deburred very well, leaving a possible source of scratches on the wing skins. So I removed these, hence those places needed priming as well.
All done, ready to tackle those nutplates!
I also deburred, final drilled and primed the aileron brackets.