Joji’s waffle stitch wasn’t working for me, so I switched to a standard mock rib stitch (1x1 ribbing on first round, knit all sts (in the round) or purl all sts (flat) on second round, repeat). This is one of my favorite stitch patterns, and I think it looks reasonably like a waffle stitch.

First swatch on US 5, knit flat & blocked:
22.5 sts x 45 rows = 4”

Second swatch on US 6, knit flat and blocked:
Somehow the exact same sts/inch as US 5 except it looks sloppier…? How. Used US 5s as main needle.

Used 10 g for swatch. Had 10g yarn leftover after sweater was complete.

I did not have enough “room” to do all the arm decreases; would have had to decrease at a much faster rate to get them all in. Cuffs are consequently looser than intended but still fine.