It was surprisingly fast getting the I-joists in place. I also ran wires from each wall to where a small exterior electrical panel will go so I don't need to route wires around corners. (All wires are 10-3 just in case and because I can.)
In order to keep all manner of critters from getting into the insulation, I installed some (shockingly cheap) rebar mesh in between the joists...
...followed by some hardware cloth and finally some landscaping fabric:
The insulation went in like butter:
Then I glued and screwed down 3/4" tongue-and-groove OSB, used an edge-trim bit on the router to clean off any minor overhangs on the edges (since I didn't quite get the tongues and grooves to fit so it got a touch weird) and called it a day.
Lessons learned
I'd spent days thinking about how I was going to attach the rebar mesh and all that stuff - relying on a simple friction fit turned out to be a perfectly fine solution. It squishes the insulation by the height of the bottom I-joist flange, but whatever. Simple is better, most of the time.
A well-sharpened machete (I think we keep one around for emergency situations?) is a fantastic tool for cutting roll insulation.
Getting router bits to stay securely in router collets is a special exercise.
Ideally, clean the bit shank and collet with solvent, rough up the shank with some sandpaper, then clean it again, prior to every use of a bit.
When I was edge-trimming the floor sheathing I was sloppy and didn't follow what I knew was right re: prepping the bit. As a result, my edge trim bit flew out of my router about two feet away from finishing the job, nearly trimmed up my leg, wrecked my router's collet in the process, plus the bit itself.
I had to buy a new router because my previous one was too old (ten years?) for the ten buck replacement collet to still be available.
I had to buy a new bit just as well - Infinity Tools is my favorite source for that.
All in all, the two minutes I saved by not prepping the bit properly cost me $250 in tools (re-)purchases. Good times.