I’m sewing it together by hand. There’s no way to do this by machine, if for no other reason that the pleating makes it almost impossible to line up the edges correctly.
The edges are finished so no complicated raw edges to turn under. I sewed it with running stitch with a 1/4″-3/8″ seam. I could only use 12-18″ length of thread at a time because it wanted to twist up on itself at any longer than that.
And yeah, I’m sewing all 4 pieces long edge to long edge into a big tube. I’ll figure out armholes, shoulder seams, and neckline after I get the large pieces together.
Fabric clips won’t work either unless you carefully make sure they are holding any pleating as pleats rather than crushing them (doable but fiddly enough that using them is likely more work than the slippiness of pins)
I have faith in your hand seaming; you were patient enough to hand sew the original pleat-gatherings so after that some nice long straight seams should fly by.
Jeannette (who’s currently knitting rows of 450+ stitches on her shawl so gets the small and slowness of it)