I thought I got off lucky with the rear window and drilling the screw holes. Completed this task back last fall and no sign of any cracks what so ever. Installed the canopy today to install the new side pins and while working in that area I noticed that most screw holes in the rear window are severely cracking. SO FAR none are cracking on the canopy, hope this stays that way. I thought perhaps I had over tightened the screws but two fingers on a screw driver can turn them. they are certainly not more than lightly snug. The only thing that changed is I have nothing to do in the hangar (waiting for the FWF kit) and turned down the heat to 5 degrees C (40 F). I'm also wandering if using the roll bar as a hand hold had anything to do with it?