I finally finished Beau.
R said something like, "well, now you can use these measurements for the next jumper you make me." I think that means success.
After re-knitting with the number of stitches called for by the pattern, I knit in the round, up to the base of the sleeve. Then I knit up the sleeves, and attached them so I could keep knitting in the round, because I am terrible at sewing sleeves in and it would have looked messy and horrible. I used a raglan decrease where the pattern asked to bind off stitches; therefore I decrease more on the sleeve side than the body. I used kitchener stitch to join the front and back at the shoulder.
I had made the body too short, so I had to undo it from the bottom, and while I was there, I did a few short rows on the back. Now it seems to be just right!
Now I think I'm going to make a clapotis for myself - I've made a few, but always for other people.