The bottom-most holes in the slider frame rear bow ended up behind the side skirts, so I used the old intersecting-lines method to locate the proper hole location in the skirt. This is the passenger side:
Unfortunately, there wasn't enough edge distance on the pilot side to put a hole there. It's no big deal, since this will all be hidden underneath the aft skirts anyway. I'll probably put the pop rivet under the skirt and call it good.
I also enlarged all the holes in the C-791 skirt brace and slider frame to #30. This photo was taken after I'd removed enough clecoes to open the canopy and escape the fuselage, but you get the idea.
Not shown in the photos above: I also spent many hours playing with ideas for the aft canopy skirts. I spent a great deal of time fooling around with posterboard templates, but didn't reach any conclusions. I think I'm going to first try the plans method of fabricating the left and right aft skirts from single pieces of aluminum… if that doesn't work, I have some ideas for multi-piece skirts. As a last resort, I'll think about making the aft skirts out of fiberglass, like this or this.