There's been a large span of time where I've done various bits (and even longer spans of time where I've done nothing at all due to weather and video games), but I estimate there's been about five cumulative days of building that I've done here and there. Time to document it!
I liked the colors that AdamSt decided upon using on his NSD, but tracking down spray cans in the States was proving difficult. I discovered a place in town (called Wesco) that could mix Chevrolet Olympic Gold (hemis, slats, gunbox details, 1 pint) and Ford Aztec Gold (main body color, 1 quart) for use in a paint gun. I also got the corresponding clear coat.
These are PPG acrylic urethane paints, and although I got the less expensive Omni system, it was still pricey. These are to be used with a compatible Omni epoxy primer. This is a two-part catalyzed primer, but the catalyst does not contain isocyanates, and cartridge breathing filters are described as an acceptable breathing apparatus. I just need to see if it can go over bare plywood/MDF, or if I need to pre-prime it. I know, I know, test it out. I will. Once I build a paint booth.
Here are the codes that I gave Wesco, for everyone's reference:
1997 Ford Aztec Gold
PaintRef.com link (Note: Both the gold  and the "tangerine-ish"  versions; I opted for the gold version)
Ford Code: M6819
1969 Chevrolet Olympic Gold
PaintRef.com link (Note: Also known as "Trumpet", "Shalimar", "Topaz", or "Antique")
GM Code: WA3922
Dupont: 5010L, 5010A, 5010D
Acme Rogers: 5562
Martin Semour: 4418
Sherwin Williams: L11-N2882
Next up, I installed the bearing ring that Gregg pointed me to. It had countersunk mounting points for attaching it to one side, but not the other. I took some masking tape and covered all the exposed areas where the bearings reside to protect them from wood and metal shards, and then I measured the center position on the bottom rotation plate. Clamping that in place, I hand-drilled through the bearing ring holes into the MDF plate.
On the other side of the of the ring, there were six plastic spacer nibs inserted into holes that were only half as deep as the ring height. In order to mount the ring to the upper dome rotation plate, I would need to drill a few of them out completely. I wanted to take advantage of those plastic nibs, though (they would provide space above and below the bearing ring for both the rotation plates), so I decided to only drill out every other hole for a total of three. I took the ring to my drill press, clamped the ring into place, and quickly drilled out the remaining depth of the three holes.
I took the ring back to the neck bin, and secured it onto the lower rotation plate using the countersunk bolts, and placed the upper plate on top of that. The center holes that were previously drilled in the plates (waaay back when I was making the neck rings) were the exact width of a screwdriver that I had laying around, so I poked that into both holes to align the plates together. Flipping the whole thing upside-down, I drew a circle on the underside of the top plate. Then I detached everything, clamped the bearing ring to just the top plate (lining it up on the circle I drew), and drilled the upper bolt holes.
The next step for me was to trim the circumference of the upper plate so that the dome would sit on it at the correct distance from the neck rings. This is done by routing a few millimeters off the plate, sitting the dome on top of it, and measuring the distance from the bottom of the dome to the bottom of the upper neck ring. (In the plans, that distance is 6.7cm.) To make sure that it's 6.7cm in any given spot, I needed to sand the bottom of the dome so that its edge was uniform and level.
I approached this by taking 40-grit sandpaper, snapping each sheet in half, and carpet gluing them to a flat board. I used the board that I used for the dome plug, scraping off the remaining styrofoam. Then I put the dome on the sandpaper, running it in circles until it was a bit more uniform of an edge. (In the picture, I still had the old acrylic light cages attached.)
The way the bearing ring is attached is with the countersunk bolts pointing down and going through the bottom plate, secured with nuts. Just before doing that, I placed bolts pointing upward through the other ring's holes (that I drilled out earlier), and secured those with nuts, too. I bought a fancy adjustable circle jig that let me make small adjustments, and went around the circumference several times. Each time I finished trimming off a few more millimeters of MDF, I put the top plate on through the three upward-pointing bolts, and put the dome on top of that to see if I was getting close to the 6.7cm measurement. I eventually got it to 7cm, and that was close enough for me.
Next steps are to take a stationary pen and draw a line around the rim of the dome while it's rotating on the bearings so that I can finally get that uniform line to dremel off and re-sand. Then, I'll cut some access holes into the rotation plates, seal it all down with PVA water, and make mounting points for attaching the upper plate into the dome interior.
Onto fender/skirt attachment: I went a little crazy with bolts sticking through the fender top when I attached the metal frame and wheels, so in order to sit the skirt on it, I needed to cut a bunch of holes where those bolts and nuts poked through. Measuring all that out was boring, and a chore, and I will totally not design it that way next time. I won't bore you with further details. The blue circles in the first pic indicate two additional holes that I drilled for large socket head screws with plastic caps attached for hand-turning. (There's a third one in the front of the skirt interior.) In the fender, I have threaded inserts that the screws connects to.
And, as I suspected from a long time ago, the gap of the uneven skirt bottom is causing some issues. I can only really get a happy medium by hand-tightening these screws, where the front of the skirt pokes up at about the same distance as the back if I tighten the socket head screws uniformly. And, the alignment with the threaded inserts is a bit tricky. Attaching these two things together at a con is not going to be a quick thing.
Finally, I found my wheelchair battery charger (it was inside my new and unused shop vac for some reason) and charged up the battery a bit. I placed it inside, added a folding chair, and sat down. I diddled a bit going forward and backward, checking how tight-fitting everything was and seeing if I needed to trim anything up. So far, so good.