Up-drilled the holes I had pilot drilled earlier. Then of course I had to take it all apart and debur both sides of each of the 4 pieces.
After that I marked up the pieces that need to be countersunk or dimpled. Note that in earlier photos I had marked up the side of the spar that had all the angles on its face. That is the view shown for the right wing spar, so I transferred all the "F" (for flush) locations to the web. But if you read the plans (!) the flush faces are on the OPPOSITE face. So I had to go back as you see in the photos here, and mark up the web on the CORRECT side.
Always remember to READ THE DAMN PLANS! :-)
Holes up-drilled, then marked for countersinking & dimpling (flush fasteners)