Detailed notes I put together from studying many others’ notes plus my own mods.

Needles
This yarn stretches greatly when wet blocked, and I didn’t like the look of such a loose gauge with the recommended needle size. So I’m using smaller ones: US6 for the stockinette and garter sections and US7 for the textured sections, since the latter is a tighter stitch. Next time I would use US8 for the textured st.

Garter tab cast on method:
Provisional crochet cast on: make chain of 5 or 6 sts, pick up and knit 3 sts along the garter bumps
Knit 7 rows, turn 90 degrees
Pick up and knit 3 garter bumps, turn 90 degrees
Pick up and knit 3 sts on cast on edge (unzip the chain sts one at a time and knit)
Total of 9 sts on needle
Next row is a WS row so I purled (except for 2-stitch garter edges)
Row 1: K2, PM, M1L, K2, M1R, PM, K1 (center st), PM, M1L, K2, M1R, PM, K2 
Row2: K2, P to last marker, K2 


Pattern
The pattern is worked from the straight neckline edge down to the point. Increase 4 sts as given on every RS row, purl every WS row, maintain 2-stitch garter border on each edge.

Increase rows: K2, SM, M1L, SM, K to marker, M1R, SM, K1, SM, M1L, K to marker, M1R, SM, K2.

Textured pattern: Sl1, K1, YO, PSSO both (continuing to increase as usual on every RS row)

Garter stitch section
Start on a WS row to avoid the bit of stockinette that would form otherwise. The increases on the outside edges are done on the WS rows; increases near the center are done on the RS rows.
I liked the look of purling the center stitch on the WS to keep the center spine uniform throughout.

Row counts
16 rows stockinette
16 rows textured
16 rows stockinette
20 rows textured
16 rows stockinette
6 rows textured (really 5, because garter section begins on a WS row)
40 rows garter or to whatever size you want

Bind off
Needs a stretchy bindoff, so I’m doing EZ sewn bindoff (takes a long time but worth it). The K2, K2togtbl, k1, etc. bindoff also works well.

Blocking
For any yarn like this that grows so much with washing, I would recommend wet blocking while still on the needles (I use Knit Picks extended cables with the plastic end caps) about 2/3 through to judge how many garter rows you’ll want.
Also because of the difference in tension between the textured st and stockinette st, the top edge of the shawl tends to curve, but that straightens out nicely with gentle wet blocking.

Malabrigo silky merino is knitting heaven, just as the label says. I used almost 3 skeins. After blocking, the wingspan is 54 inches.