I modified the cable charts so that the cables slip over the stripes; my cable charts are 30 rows instead of 22.

I had planned to also modify the pattern to work the fronts and back separately and seam them, to make the self-striping yarn stripes move through the colors more slowly… but then I impulsively changed my mind and joined the pieces as the pattern is written, hoping the stripes still look okay!

Update: finished! I ended up using two different rainbow Felici colorways, so the dark rainbow blends into the bright rainbow. I kind of forgot to keep track / pay attention to my quantity… I THINK it only used 3 hanks of Twill and 1 skein each of the two Felici colors, but I could be mistaken.