Yeah! It worked. You can see a bit of a seam where I used the kitchner stitch, because the back of the cardigan is in reverse stockinette and the front shoulder is stockinette. Didn't think of that earlier, but I like it much better than the original directions!
So, my next question is: instead of knitting the sleeves flat, joining and seaming. Do you think I could pick up stitches around the arm hole, and work my way down the sleeve, decreasing as neccessary? Or is there a better way?