I have an old, handmade CB loom with rollers, and have successfully used it for doubleweave and TONS of lace weaves that require 1 v 3 shafts. When I started, I didn't know I wasn't supposed to be able to do it, so I just did. I do sometimes shorten the Texsolv cords that go from my top roller to the other 2 rollers to make the shed a bit bigger, but in general haven't found it to be too much of a problem. And I don't think my little loom has a particularly large shed even when I'm weaving 2 v 2 shafts.