I know that there are some folks out there who are interested in making this sweater (or already have it on needles!), so I wanted to be fairly comprehensive in my notes.
You may remember that when I started the sweater, I gave a rundown of the two versions of the pattern, so I won't repeat that info. It took me a while to decide which version to make, as the sizing and shaping were slightly different, but I finally decided to go with the version in the Rowan Vintage Knits book, for the most part. This is the pattern that included a size XS, although if the pattern were to be believed, the finished product would have the same chest measurement as only size on the other pattern, which has the same number of stitches as the size S.
At any rate, I threw caution to the wind and cast on without a clear plan in mind - after doing my gauge swatch. As I'd suspected, I needed to use a 2.75 mm needle (US 2) rather than the 3.25 mm (US 3) the pattern suggests. This seems to be my standard needle size when I use 4 ply yarn.
Because I don't like my ribbing to be binding at the waist, I did the ribbing in the same size needle as the main fabric. I cast on the prescribed number of stitches, ribbed for the prescribed number of centimeters, and increased as written. So far so good.
Going back to the pattern I decided not to use, I did two full repeats plus six rows of the striped feather and fan pattern. According to the pattern, at that point I should have been at 29 cm total, and I may have been if I hadn't steam blocked the work as I was knitting. (I often do this to get an idea of how the finished fabric will look.) I ended up at 31 cm when I reached the armhole, better for me since I'm long waisted. This is important because it does affect the pattern later on, when the sleeves are attached. If I had followed the pattern I was supposed to be following and begun the armhole after 28 cm, my stripes would not have matched up across the upper chest and sleeves as they do.
Having reached the point of beginning the armhole shaping, I had to make a decision. I was originally drawn to the shaping in the original pattern (the one I wasn't using) for two reasons: it didn't have a shaped sleeve cap (and would be therefore much easier to work while keeping the pattern stitch correct) and it looked like a much better fit on the model. I had decided as I went along that I would mix and match, and do the flat (unshaped) sleeve with the body of the smaller version of the pattern. But as I read ahead, I realized that this would have made the shoulders far too narrow, so I went with the shaped sleeve head after all.
And it really wasn't that difficult to keep the pattern correct, but you do have to remember that for every yarn over there has to be a corresponding K2tog. As I decreased stitches, I kept the pattern correct as much as I could, and kept whatever leftover stitches I couldn't use at the edge in stockinette. I did choose to make things easier on myself by omitting the final decrease for the armhole - that kept the counts at 6 and 12, so I wouldn't have to remember to adjust my YOs every time that row came up. When I got to the shoulders, I just added that stitch into the count for the shoulder bind off.
Although it was a little harder to keep things correct on the sleeves (thanks to my nemesis, Netflix), they were nice and quick to knit. I was tempted to start the stripe sequence from the beginning rather than in the middle as the pattern states (I'm a little funny that way), but luckily I realized that the pattern was written that way for a reason. That reason being that the stripes match up with the stripes on the body! Wonderful, and it also made sewing it together a breeze because you always know just where you have to be.
Up until the very end, I was worried I might not get a very flattering fit, mostly because the sweater looks like a stripey sack on the model in the book. Having finished it though, I now know that they just gave the poor girl a sweater that was much too big for her! The fit across the shoulders is just perfect, and in the end I think it is probably more flattering than the other sleeve shape would have been on me. The sleeve head sits toward the outer edge of my shoulder, which I find is a rather vintage silhouette and very comfortable to wear.
I mentioned I did a gauge swatch (as I always do, since I am such a loose knitter) and I got gauge with my 2.75 mm needle. If the pattern were to be believed (which it is not), I should have ended up with a finished bust measurement of 36" (for both XS and S - go figure). What I actually ended up with is a finished measurement of 34", which for me is 1" positive ease - the perfect amount for this look.
I finished it up with my 2.25 mm needle (US 1) for the neck ribbing, and a good dose of steam helped everything lay straight at the end. I've mentioned a few times in the comments that I tend to block most things with my steam iron, on high heat and full steam with the iron hovering just above the knitting, but never really touching it. For me, this gives the fabric a much smoother finish, although it doesn't seem to even out stitch tension as much as wet blocking. My tension tends to be pretty even though, especially with wool. And steaming is just so much faster.
So there you have it! Extensive and technical, and probably soporific as well! My hope is that it's useful information for someone!