My stitch gauge is 1 stitch out, but row gauge is correct, so I’m modifying the pattern to end up as 41”/42” chest.
I tried 3.5mm, but the fabric was so much nicer on 3.75mm.

Lets see how it goes!

I started with the smallest size, then knitted as pattern to the last set of raglan increases (after resuming to knit in the round, page 5, bottom of left hand column))
Here, I did 15 of the last 2 rounds (rather than 14), then increased for the body only another 3 times = 6 more rounds.
That gave me 108 for each front and back, and 67 for the sleeves, the same as size 2.
I continued with size 2 for the rest of the body and sleeves.
It’s worked out perfectly…

Body/ sleeves on 3.75mm
Ribbings on 3.25mm
Neck on 3.5mm

2 stitch icord on 2.75mm, 42” long. I tried a 3 stitch on 2.5mm, but it was too thick in this yarn.

Total weight (without the cord), 560g, 1344m.
Icord weighs 4g, 4m

Measurements after blocking:
Chest, 42”
Underarm, 19”
Length (from top of shoulder, next to neck), 26”. From front of neck in the middle, 25”
Neck height, at back, 6”
Neck width, 12.5” (25” circumference)

I forgot to knot the ends of the icord before taking the photos, I’m not taking them again!