Feel free to use the mosaic chart
22 stitches and 32 rows

With black, I cast on 66 stitches. I use long tail thumb method of cast on. I don’t count the slip knot and transfer it to the right hand needle when all stitches are cast on. I then knit or purl it together with the last stitch on that needle when I come to it to prevent any jog/gap at the edge.
I use 3 needles and knit with the 4th. So there are 22 stitches, one pattern repeat, on each needle.

I did 2×2 ribbing for 10 rounds. Which, duh, meant I started and ended with 2 knit stitches. Oh well, it’s black yarn, no one will notice. I quess I should have done 1×1 rib instead.

I did 2 full pattern repeats. On the third repeat, I knit in waste yarn (#3 crochet cotton) for the thumb between row 31 and 32, to not interfer with the skull pattern. Using white, I knit all of row 31, then on row 32 I knit 2 stitches, then 8 stitches in crochet cotton -- leaving the tails on the outside. I then transferred those 8 stitches back to the left hand needle and continued working the pattern in white.

Another good place for thumb placement would be between rows 15/16 between the second skull motif.

I haven’t done an afterthought thumb before. I used these instructions: https://maryjanemucklestone.com/all-thumbs/

After the placing the yarn for the thumb and completing row 32, I did one more repeat. So 4 repeats from cast on and ribbing. I then did 2×2 ribbing for 10 rows and bound off in rib.

I picked up the 16 stitches (8 top & 8 bottom) of the thumb and added 4 stitches at the corners for 20 total stitches. I did 2×2 ribbing for 10 rounds and bound off in rib.

They are a little snug on my hands and the thumb opening is a little tight. My hand circumference is 8” and my thumb circumference is 2 1/2”. It could partly be the yarn choice, Woolike is mostly acrylic so it doesn’t have the stretch of wool.

However, I’m trading these to a friend who sews for 2 masks. Her hands are smaller.

Each mitt is 9 1/2” long, from cuff to cuff.
Each pattern repeat is approximately 1 3/4” tall by 2 1/4” wide.