My yarn’s a bit heavier than 4ply but a UK size 12 needle (2.75mm) seems to give the right tension. I held the shoulder and back stitches on stitch holders, then used the 3-needle method to join the shoulders, knitted the sleeves in the round, and did an I-cord edging instead of the 5 knit rows, as I was running out of wool. It’s now a nice tweed winter coat!