I decided to try and write down what I figured out. Hope it's useable.
Sweater for a tiny dog – 12” chest – 3-1/2 to 4 lbs. (disclaimer: first pattern I’ve ever written down, not that professional. Just give it a whirl)
Use sport weight or baby sport weight yarn
DPN’s size 4 (or 12” circular needles)
Cast on 44 stitches. Join in the round and knit in a 2 x 2 rib pattern for about 2 inches. (more if you want to fold it over like a turtleneck). Place a marker to keep track of the beginning of the row.
Change to size 6 DPNs or 12” circulars. (Addi makes this size)
Knit 1 row-place markers for the armholes as follows:
1st marker is the one that is the start of the round
knit 4 (arm)
knit 6 (chest)
knit 4 (arm)
(4 markers total)
Now continue knitting in a circle. Every other row do an increase
(k f b) on each side of each marker (total of 8 stitches added.)
Continue like this until the raglan line measures 1-1/2 inches. The 2 arm sections now need to be done in 2x2 rib again, for an additional ½” (this will prevent curling). The rest of the stitches are still knit – not rib. Total length of the raglan line will be 2”.
Now when you come to each arm section you will bind off those stitches, then knit the chest, then bind off the next arm and go on around again. (note, I did a picot bindoff for a fancy edge)
As you come to the underarm, just knit the next stitch so the arm bindoff stitches turn into the armhole. You’re joining the chest section to the back now. Knit until total length from cast on edge is 4-1/2”. For shaping, k2 tog on every 6th stitch. Knit until total length reaches 6”. Now we have to bind off the middle 8 stitches (under the belly). You will work back and forth now – knit a row, purl a row. At both ends of the row, k2 tog or p2 tog on every row. At 7” length, change to size 4 needle again, and begin doing the 2 x 2 rib again. Continue for ½”, then bind off in picot edge if desired.
Have fun! WOOF