I managed to clear a space in the chaos that has reclaimed our condo (why is that battle never over?) and pulled out my sewing machine to do the deed. Better knitters than I have expounded upon hand stabilisation methods, including simply trusting the wool to grab itself; however, until I move on to authentic Shetland wool, I feel most secure with machine sewing. (Besides, if it was good enough for EZ....)
1. I got brave this time, and made a measly 4 stitch steek. (I've seen EZ use only two, but I'm not quite ready for that yet.) Below you can see the four stitch column, with pins inserted up the middle to ensure I don't lose my way on the dark gray yarn. (BTW, a couple of commenters and family members think this sweater is blue - does it look that way to anyone else? I'm wondering about my monitor.) I chose good cotton thread (no polyester sullying my wool), and the widest zigzag setting, with the centre mark of the presser foot aligned between the two stitches to be stabilised. (I haven't seen zigzag discussed as a means of stabilisation - I find it preserves the elasticity of the knit fabric, while also functioning similarly to two rows of straight sewing.)
2. I sewed down the two stitch column on each side, being careful to reverse for a short way at top and bottom to be sure to catch the edge stitches. Red denotes the cutting line, and green is the space in which stitches will picked up for the sleeve.
3. The deed is done!
See? Not so scary!