Gauge looks to be perfect after blocking, on 3.5mm.

Followed the pattern as written, including the length of body. I just added some length to the sleeves.

I found the easiest way to do the neck welt was to pick up the purl bumps immediately under the needle after round 4, using a smaller needle with a long cable. You can just let the cable hang until you need to knit the stitches together. That way there are no needle tips next to each other to make the 5th round difficult.
When doing the hem welt, I picked up the purl bumps straight after the last round 4 of the body (just before changing needle size).
Then I knitted 5 rounds on 3.25mm, then did the K2tog round. I knitted 3 rounds after this (rather than 4), then bound off knit wise.
I found it also helped to section off the stitches when they’re on 2 needles, before doing the K2tog (I put removable markers every 30 sts). Then it’s easy to check that the stitches are right each time you get to a marker.
I do the same with a 3 needle bind off when there are a lot of stitches, there’s nothing worse to get to the end and find more stitches on one needle than the other, then have to backtrack hundreds of stitches to find out where the mistake is

The body weighs 167g (665m).
The body plus one sleeve weighs 205g (816m).
One sleeve has taken 38g (151m).
Finished weight, 243g (967m).

I added some length to give a 19” inside sleeve, and finished with Anke’s invisible bind off, which looks like tubular, but is easier and faster (but not as stretchy):
https://www.youtube.com/watch?v=TaBwcX8estY

Measurements, unblocked:
Length, from top of shoulder next to the neck, to hem, 22”
Bust, 38”
Body, from underarm to hem, 14”
Inside sleeve, 19”

After blocking, it had stretched bit:
Length, from top of shoulder next to the neck, to hem, 23”
Bust, 40”
Body, from underarm to hem, 14.75”
Inside sleeve, 20”

I might take the ribbing out from the sleeves and shorten them a bit, but I’ll wear it first and see…sometimes they can shrink with all of the elbow movement.