I just set the door panel against the door and moved it back and forth just enough to scratch the paint. Marked the spots and drilled the holes. Checked and rechecked alignment after each hole. I dont remember what size I used but it was pretty big. Somewhere around a 1/2 inch bit. If you make them too small good luck getting the panel off if you ever want to again. The clip will tear out of the panel befor it comes out of the door. Jim
My instructions say 3/8 inch but I agree that 1/2 inch would be better. I think the clip will probally pull out with the smaller hole. IF you have problems call BJ's Upholstery, 20235 Follage Road, Granby, MO at 417-325-6297. That is who made my interior for B&B amd the number they put in my package. Hope this helps.
Chris
I found my instructions after I had about 90% done. I dont remember a size for the holes written in the instructions. Drill a hole in some scrap plywood and see how the clips fit. Jim