It took me a while to understand why I shouldn’t join the round right away, but suddenly it all made sense! Yay!

Since I was working with a different yarn (and my biggest circulars are 5.5 mm), I had a suspicion the sleeve sections wouldn’t be wide enough if I stuck to the pattern word by word, so I just kept on repeating the 2 rounds (1 w/o increases, 1 w/ increases) until they fit (at which point each sleeve section measured 47 sts; no additional CO; body: 128 sts).

k 10 cm (27 rds), then started decreasing as follows (inspired by the last pullover I knit):

A: decrease rd according to pattern
B: k 5 rds
repeat 3 more times

---- waistline

increase rds:
A: k 5 rds
B: increase rd according to pattern
repeat 3 more times

Then about 5 cm straight, then 3 cm of 2x2 ribbing.
BO in pattern.

Sleeves: Picked up 48 sts on each side with DPNs; sewed the resulting holes shut afterwards. k more rds than strictly necessary, consequently kept the ribbing down to 3 rds, BO in pattern.

Neck = 2 rows of single crochet (so as not to cause more holes).