A Knitlister suggested casting on one stitch at a time, then working in pattern before casting on the next stitch
Sorry ... this doesn't make any sense to me in the context of a making a strap, so I wouldn't do this. Using the knit-on cast method, I would cast on all required sts, then work the rib.
I know some people would use the backward loop to cast on in the middle of a row, but I've never had any luck with it because it's so loose. Check out Amy's Videos
to see both the Knit-On CO and Backward loop CO.
the one you're making? :thinking: