Angle of the Weft
I am using a draft from Carol Strickler's A Weaver's Book of 8-shaft Patterns (#59, page 20). In the twill-variation tie-up, some of the treadles raise every other thread (shaft), and others raise 4 (with 4 down). Should I vary the angle of the weft (more for the plain-weave lifts, less for the 4/4 lifts) to keep the selvedges consistent? Is this something to consider when you use any draft that varies the rate of interlacement?
I think the difference in the interlacements among the treadles used in that tie-up is not great enough to matter, even though the weft take-up in the picks with more plain weave will be a bit more.
Even with overshot, I don't usually find the angle the pattern weft is happy with to be that different from the angle the tabby weft needs, and they are at least as different as the interlacements in this draft. For wide pieces and for yarns with little resilience (linen), you may need to take this into greater consideration.
You can always tell if you do need to adjust the weft angle, though, by noting whether or not some of the picks are causing too much draw-in. In that case, you'll want to use a steeper angle. If the angle has to be especially steep (as for wide, weft-faced pieces), you'll need to bubble the weft to make the distribution of the yarn consistent across the width of the warp. Using a temple also helps minimize draw-in, especially for wide pieces.