I found one picture (below) of an installed pair. I can head out to the shop and take some pics of the square notch details if you need them.
For installation it should be pretty straightforward. The panels slip over the sail panels, and follow the rear glass. The panels will rest on the glass rubber weatherstrip.
The one panel with square notches ends up with the notches in the center of the roof/window The panel with four holes lays on top. In the end you can visually see 6 screws, 2 on each end and 2 in the center.
Here is an alternative approach to pricking and marking the headliner.
1. Using the sail panel as a guide, prick and find the holes there.
2. Take the panel with four holes (not the notched one) and run the two known screws in half way.
3. Line the panel up with the rear glass.
4. Using the panel as a guide, prick through the holes to find the screw hole close to the glass. Should not be far away.
5. Install that screw just enough to stay in, then you might be able to slip the notched panel above it.
6. Find the two holes near the sail panel, then the other center one away from the rear glass, and after that should be smooth sailing.
There are a lot of ways to skin a cat. I'm thinking that using the panel as your guide it will get you to within 1/4", probably better, of your destination.