I finished my språng pullover. You can see it is more of a waistcoat than a sweater. It is in the Skrydstrup pattern from Collingwood's The Techniques of Sprang, so four rows of S twist alternate with four rows of Z twist. The pattern of twists cause the fabric to curl a little but not distort to one side the way all Z twist would. The curl is visible in the edges of the armholes.
I am more pleased with it off the loom than I was when it was on the loom.
The drape of it makes the armholes look curved but they were done straight.
The construction is a lot like what we used to wear in kindergarten to keep our clothes clean while fingerpainting, a plastic garbage bag with holes cut for the neck and arms. Except you don't cut språng just anywhere. I didn't cut this piece at all.
The hole for the neck is a slit formed by treating the threads on either side as a separate section. You work to the middle of the row, move the threads as if you'd come to the end of the row, move the next threads as if you were starting a row, and go from there. I picked the easiest row in the pattern to start this on, row 7.
The armholes are formed by seaming the sides partway. They look rather deep but they are correct because when you put on the vest, the fabric stretches horizontally and shrinks vertically.