Gauge Swatch Theory question

I’m currently knitting gauge swatches for this sweater:

Suggested Needles: US size 4 and US size 10
Gauge is:

14 sts + 18 rows = 4 in. (10 cm) in St st (k on RS, p on WS) using larger needles with 1 strand each of A and B held tog.

21 sts + 30 rows = 4 in. (10 cm) in K1, p1 Rib using smaller needles with 1 strand of A, slightly stretched.

I’m starting with a swatch for using one strand of yarn in the ribbing portion of the pattern. I seem to have to go up to a size 6 needle in order to get gauge for this pattern. If so, would you (or “could I”) assume that I’d have to go up the equivalent number of needle sizes for the larger needle in order to get gauge for the double-stranded part, thus enabling me NOT to HAVE to swatch for that as well. Or should I start swatching that part with the recommended needle size (10) and go from there.

I know, I know…there are no shortcuts to swatching. I’m just spitballing here and wondering what others think.

You might start with size 11s and both strands to see if that works for you. Just continue on the same piece as your ribbing, no need to do a separate one.

Seems like two strands of cotton would make an awfully heavy top.

One strand is recycled cotton and the other is cotton bamboo and it’s really light. Shouldn’t be too heavy.

I was planning on keeping going on the same swatch when I change to the larger needles.

Oh, how I detest swatching. It frustrates me to think how much I could have finished on the piece itself if I didn’t have to swatch.

But if you finished it and it’s the wrong size, you’d have to do it over. Better to swatch and have it come out right. Think of it as ‘playing’ or trying out the yarn and needles to see what it looks like.