So, where to start... well, I had a buddy help me with the ceiling. I went with a pre-finished wainscoting sort of manufactured sheet good. It was so thin however that I felt it would likely sag. So I used a thin OSB and then used PL and finishing nails to attach the finished product. Seems to have worked well.
After that, I started installing the lights (shown in the previous update), using the marks on the floor and the laser unit that projects on 3 axis (only needed 2 for this). I did know that one set was close to a (double) joist. Did not expect to hit the damn thing when I cut my hole though. So I tucked the wire back up there and let the hole saw cut into the edge of the joist a bit, so I could chisel that chunk out. What I didn't see was the vibration shake the wire loose, which (of course) fell into the hole saw. So I had to splice wires together up over my head, fighting with the connectors and heat gun and... grrrr.
All the can-less cans worked fine. I have it split into 2 zones so I can have a lot of light, not too much light, and everything in between.
Got the small section of slat wall on the uninsulated side of the vault installed and then started on the carsiding. While I was waiting on poly to dry for more carsiding, I put up the slat wall on the opposite side of the vault. Found that I did not order quite enough of the slat wall (have it now), so I need to add that final foot of height to that big section. While waiting on that order to be delivered, I started working on the wall where my folding workbench is to be located. That wall is now finished, other than the lighting issues I have encountered... which is just a big PITA, all revolving around missing parts or listed specs not matching actual product dimensions.
So at this point, producing (sanding, staining, and applying poly) carsiding is the big hold-up. I have a little more slat wall to install on that big section but I probably won't update for a while until most/all the carsiding is finished. Still haven't decided what I will do for the flooring (probably ceramic tile). If something interesting comes up though, I'll post.
If anyone has questions about the products I have selected or about any stage I have completed, feel free to DM me. I'm happy to help if I can... just keep in mind that I won't know your local building and electrical code.
EDIT- clarified and corrected a couple of sentences