The glove box has worked well for a few months, but it was ugly. There are large gaps between the box and the dash and the paint is damaged where I cut the door out of the dash. To finish the job I need to add a flange behind the door and repaint the dash.
Making a flange behind the door is actually quite simple. Mike Arnold shows a really cool technique for making door with very tight clearances (small gaps) in his AR-5 videos. The technique is to cut out the door, which was already done, then to wrap the edges of the door with duct tape, making sure to tape in as far as the flanges are supposed to go. Reinforcing resins will not generally stick to duct tape, so once the edges of the door are tapes, mount the door in place where you want it. Then mix some filler (talc and resin) and fill in the gaps then lay up a few layers of glass behind it (over the duct tape). Once the resin has set you can pull the door off and you have a perfect flange behind the door.