Prepared right back window. Trimmed to size. Marked with a specific marker to have 3/16" gap on the flange. Used a disk sander to trim. Sanded with sanding block and 150 grit sandpaper.
Installed the glass in the window. drilled #40 and clecoed the window using screwclecos and little wooden strips. Marked the flange for easier positioning later. Marked the inside glass with red marker (normal marker to be cleaned with alcool later).
Masked outside and inside, but the tape didn't last enough and i had to redo the whole positioning and marking.
In the meantime i put dabs of sikaflex on the window flange to have the shims already in place.