I laid out and drilled the side skirts per plans...

...then clamped them in place on the side rails and transfer drilled through.

Here's a closeup of the fit at the aft end.

At the forward end, I used the overlapping canopy skin to mark the cut line.

Fits well once trimmed.

I noticed that, because of the presence of the joint plate, there is a considerable distance at the aft edge of the canopy skin that won't be riveted, so I decided to add a rivet at this location.