After all that making balls of denim strips, the actual weaving was pretty uneventful. The warp was rug warp, 10 epi (ends per inch), super easy to thread (straight draw) and sley (1 per dent in a 10 dent reed).
The weaving was pretty uneventful, as well, except that I brought the Fireside loom to its knees. The high tension was over the top, and I actually caused the back beam to bend downward (it is bolted on, so technically it COULD, but it shouldn't!).
Loosened up the tension a bit and kept weaving. The instructor has a friend who Fixes the Looms, and someone on Ravelry had shared that HER Fireside had some wood pieces on top of the back beam arms that kept it from rotating downward. He came by, we looked at the other, properly-equipped Fireside loom, and a few weeks later I came in and found them installed.
The weaving went SO QUICKLY!
Then I wound a warp for another rug, for the downstairs bathroom. That was quick, too.
Learnings:
For the headers, weave with the carpet warp held double, otherwise it will pull in, no matter how hard you try for it to now.
Maybe don't weave rugs on a jack loom that has a hinged back beam. :-)
That said, the rugs have been in use for months now. I toss them in the washing machine from time to time.
Friend P got a HUGE stash of denim strips. She gets to skip all the hard parts.