anemoi cuff

argh! this is the beginning of my Anemoi Mittens. (pattern at eunnyjang.com) this cuff is HARD!
I'm a little confused about the tubular cast on - if you follow the directions for that, then the first "set up row" has you knitting the purls and purling the knits - I don't know if I did that right.
and then, you have to purl the contrast row with your left hand! (sort of - I mean, you probably don't HAVE to, but...)
I'm only sort of managing that, I need my right hand to help.
And, I had to use the same size needles I'm using for the rest of the mittens - size 6, because I'm also using sport weight instead of fingering. I knit so tightly that I'd NEVER manage the right gauge with fingering. (I tried the cuff first with a size 5 and it wouldn't have fit over my hand.)