Latvian-inspired mitten pattern

Here's the pattern for my "Latvian" mitten:

Requirements:
size 4 double-pointed needles
Karabella Aurora 8 (94 yards/skein) or other worsted weight yarn: 2 skeins color A, 1 skein color B, 1 skein color C
Tapestry needle
waste yarn

Ladies' size small
Gauge: 26 stitches and 28 rows = 4 inches

CO 40 stitches in color A. Knit 1 row, then join yarn in the round. Knit 3 more rounds, then *K2tog, YO, rep. from * for one whole round. Knit 4 more rounds.
Switch to color B and begin pattern chart. Notice that some rows require you to increase or decrease by a stitch or two in order to fit the whole pattern repeat, and in switching from the wrist patterns to the main hand pattern you will increase by five stitches.

* note: the red centers of the main pattern's boxes, as well as the white centers of the cuff pattern's diamonds, can be done in duplicate stitch if preferred. If you choose to do so, just knit the boxes entirely in white and the diamonds entirely in black.

Dark outlines on the chart indicate where to place thumb gore for left and right mittens. Inside this outline, increase as charted for length charted. At final row of thumb gore, knit row, then place thumb stitches on a length of waste yarn. In the next round, knit to thumb stitches, cable cast on 3 stitches to make up for 3 original thumb gore stitches, then continue round.

Decrease for top of mitten as charted, using right-leaning (k2tog) decreases on right sides of mitten tops, and left-leaning (ssk) decreases on left sides of mitten tops. When four stitches are left on needles, break yarn, draw both colors through loops, pull through to wrong side of piece, and knot.

Pick up thumb stitches from waste yarn and pick up 11 stitches around hole left by thumb gore, continuing the stripe pattern. Join yarn and knit in the round until thumb reaches about 1/3 of the way up the thumb nail. Begin decreasing by four stitches in each round as charted. When six stitches remain on needles, break yarn, draw through loops, pull through to wrong side of thumb, and knot.

When mitten is finished, fold under and tack up picot hem. Weave in all ends and block mittens together to make sure they are the same size.