size 6, Aslan Class yarn, for me
LTCO 60
4 rows garter, 10 rows stockinette
k30, pm, YO, pm, k30
purl back
k30, sm, YO, k1, YO, sm, k30
purl back
repeat previous 2 rows, widening area between markers, until 29st between YOs, 91st total

knit plain in stockinette (across back)

CO second sleeve, knit identically, graft to first piece

mattress stitch seam up the sleeves to allow desired sleeve length and cross-back width

size 8, Premier Cotton, for kiddo

as above, except LTCO 36
increase until 17st between YOs, 55st total