Tonight I scarfed the overlapping forward corners of the right wing top skins to prevent the bulge at their intersection with the tank skin. I started by partially clecoing the two skins to the skeleton and masking the outboard end of the inboard skin accurately at the inboard edge of the outboard skin. This will mark the inboard limit of the scarf of the corner and the scuffing of the entire width of the faying surface of the top skin so as to not mar the surface that will show. (I still haven't totallly given up on eventually polishing the airplane).
One building tip that occurred to me was to cleco the corner of the skin to a piece of 1/4" plywood for support while scarfing. This allows scarfing at any chosen angle without the sanding block hitting the bench, and prevents bending of the very thin corner. The same drill pattern works on both the inboard and outboard skins.
I only have to lightly scuff, clean and prime the faying surface of the top skin, and the scarfed corners of both skins to get them ready for dimpling. I'll then repeat for the bottom skins.
Inboard top skin masked for accurate scuffing and priming of the faying surface.
Corner supported for scarfing by a scrap of plywood.