I am knitting a cable jumper and the back panel is supposed to follow the same cable pattern as the front however I would like to knit it in stocking stitch instead. Should I cast on the same amount of stitches as if I were knitting the cable? Or do I need to cast on more/less?
It depends on how large the cable panel is but even a 2x2 cable with a couple of flanking purl sts will pull in the width of the back. If you’re going to eliminate the cable panel, you can cast on fewer sts. You can determine how many fewer by knitting a swatch with the stitch for the back and stitches for the cable panel and measuring the difference.