First square as per pattern, but had a lot of cable flare (see comparison picture)
Second square, followed recommended modifications and cast on 40, two rows of seed stitch, increase 8 stitches before cabling. Then decreased 8 stitches and did two rows of seed stitch before binding off.
One row of DC around each square, then joined with whip stitch and bordered full piece with a row of SC and then a row of HDC.