Drilled the canopy holes after final alignment of the canopy on the frame. Initiially drilled with #40 then final drilled with #27. I used a standard #40 bit for the initial holes then a home made #27 plexi bit for the final drilling. It's a little tough to do the match drilling with the plexi bit as you have metal to drill through after going through the plastic and the plexi bit is great for plastic but not so great for the metal. Holes came out nice and clean with no cracking or chipping (so far). Once the glare shield is painted flat black and the from fiberglassing is completed, the holes in the plastic will get counter sunk for wither a dimple or a screw head.
