After weaving an inch's worth of picks (24), I took a close hard look at what I was getting. The last inch of warp at the left (dexter) selvedge was weighted twice as heavily as the rest of the warp. This was due to my seat-of-the-pants call that two inches of warp was an appropriate number of ends per warp weight.
It was a hard decision, and I dithered for a couple of days before actually doing it. But I elected to untie and redistribute the weights across the entire warp. I didn't have enough extra loom weights to do the whole thing at 12 ends per weight, though. I did have enough to use an inch and a half (18 ends) per weight rather than the two inches (24 ends) that I had on the loom originally. So I've re-weighted the entire warp.
Now I'm working on beating that first "inch" of picks more tightly together, because it measures somewhat more than one inch in length. The heavily weighted area measured something less than an inch; I will also try to spread out the weft in that section a bit so the density is the same all the way across the warp. I am hoping I have found a happy medium that will give me a nice texture of (mostly) evenweave.
I'm also happy that the weights are distributed completely evenly across the warp now. Also, because it is more firmly stretched the warp makes a different and more clear sound now when I strum it. I feel much more optimistic about the project now.
Back to work!