(I made it less than the full width of the nozzle for reasons which turned out to be dumb.) Doing it this way gave me a butt joint instead of an overlap, which I’ll be able to fill and smooth later.
That was my first one, which turned out to be too small, so I did another one. Then I glued it into the top of the nozzle. I’m not sure there’s anything to be gained by using the provided reinforcing ring, but I figured it couldn’t hurt. I probably should have filed a notch in it to accommodate the glue tab, but I didn’t.
I took my bike to the bike shop for a tuneup about a month or so earlier than planned, because they were having a maintenance sale. Said bike shop is across town, and you can practically stand at its front door and throw rocks at Radio Shack. Which was tempting, but instead I went in and bought some nuts and washers. A lot more nuts and washers than I’ll ever need, I assume. Back home I used one of each to secure the nozzle to the threaded rod. For flight, of course, the nozzle comes off, and the same nut and washer — or different ones, if I drop the first ones and lose them, which seems likely — retain the motors.