I knit this in a size 7, with significant pattern modifications to accomplish two main goals: knitting flat instead of garter in the round and raising the armholes for better coverage.

I’ve noted my modifications below. These are made to fit my body. If you use these mods, you should try on as you go to make sure they work for you. A mid project block after finishing armhole shaping is recommended for sizing.

Shoulder Straps:

I found the straps too skinny for my preference and to cover my bra straps. I cast on 7 stitches for each strap instead. Follow all other directions. Final stitch count before joining in the front/back is 10 stitches on each strap.

Join The Front/Back:

Row 1: When casting on additional stitches using backwards loop, cast on eight fewer stitches than pattern calls for to account for wider straps.

At first repeat section, repeat rows 3 & 4 eight more times instead of thirteen.

From here, the pattern instructions vary based on the size you knit. Note that these mods are based on a size 7, and adjust accordingly for other sizes.

For the second repeat section, to shape the armhole openings, repeat rows 1 & 2 ten more times instead of fifteen, so that there are 92 stitches in total. (Alternatively, continue as written to keep a deeper armhole)

Then, diverge from written pattern as follows:

Row 1 (RS): K1, M1L. Repeat from 6 times. K until 6 st remain. M1R, K1. Repeat from until end.
(This makes up for the extra stitches that were skipped by stopping the armhole shaping repeats early. Make sure to add an additional stitch to each side to account for seaming at the end of the project. For a size 7 you should have 102 stitches if following the pattern, but I cast on an extra 2 for a total of 104 stitches)
Row 2 (WS): K across
Row 3 (RS): K across
Row 4 (WS): K1, wyif SL1pw (this creates the side detail)

Repeat rows 3 & 4 until desired length is reached, making sure to keep row count the same for the front and back.

Hem:

(Note: I did this once the front and back were complete but before seaming to avoid picking up stitches. Alternatively, break yarn, seam sides, and pick up the appropriate number of stitches for the hem.)

Row 1 (RS): PM (BOR) k2tog, knit across until 2 st remain, K2tog. PM. Join other in the round by continuing k2tog, knit across until 2 st remain, k2tog.
Row 2 (RS): slip BOR marker, wyib SL1pw, purl to one stitch before next marker, wyib SL1pw, SM, wyib SL1pw, purl to one stitch before BOR marker, wyib SL1pw

Follow pattern instructions for icord bind off.

Seam sides using mattress stitch. Follow pattern instructions for armhole and neckline edging as desired.