Now, back to knitting. As much as I don't enjoy swatching, I have to admit it is indeed a good practice. Since I had reached the armhole shaping in the Leftovers Tank, it was time to get serious with how to proceed. I already figured out the number of stitches in the shaping, what was left to do was the double knit slipped stitch edge (from Annie Modesitt's Confessions of a Knitting Heretic).
I did a little swatching following the instructions in the book: