I'm now tackling the task that I dreaded. Out of every skill associated with this project, the only thing I hadn't actually done before was lash an entire shed of the warp to a stationary shed rod. I had no trouble figuring out how I wanted to work the lashing. It took some thinking to figure out how I wanted to keep it even: I decided to just go ahead and mark the rod. It took me even longer to work up the nerve to try it.
So first I began lashing the warp ends in groups of three. After an inch I got brave and tried groups of two, then finally tried lashing every warp end. I can do it! It's very fiddly at this sett, and the bobbins I'm using to hold my thread are less than optimal. I'm using 4" boat shuttle bobbins; I'd prefer using tapestry bobbins but don't have any.
I finished 5" of lashing and had to take a break because my eyes and threads were crossing so much! Instead, I finished weighing all my new loomweights.
The new weights range in weight from 193 to 224 grams apiece. Most of them (87 of the 120) weigh somewhere between 207 and 216 grams. There's one extreme outlier at 193 grams, and a nearly perfectly matched pair at the heavy end that I've earmarked for the selvedges.
I expect that lashing the shed will go somewhat like lacing the header band. Sooner or later I'll figure out a really quick, simple, ergonomically superior way to do it and it'll go smoothly. Until that point, I'm going to be pretty twitchy.