I didn’t want to make such a dense fabric, so I switched yarn weight & needle size.

I knit just 8 rounds after the thumb stitches were set aside & before the colorwork rounds. I did the chart, but really wasn’t pleased with it, so ripped back & made up my own. Tan yarn held in right hand.
1 - tan
2 - garnet
3 - garnet
4 - alternate every other stitch, starting with tan
5 - alternate every other stitch, starting with garnet
6 - alternate every other stitch, starting with tan
7 - garnet
8 - garnet
9 - tan
10 - garnet

Like that much better!

I did just 6 rounds of SS on the thumb before the ribbing. .