Gonna be a great set!
Plentiful Hat

Ch 86 for more circumf.

Recommendation # 1
It is hard to begin with many many chains, join without twisting and commencing with hdc’s (or dc’s).
Work foundation stitches instead, such as fhdc or fdc.
Even if you work your cowl in hdc, doing the first row in fdc makes the next row with post stitches much easier.

Recommendation # 2
Work a few rows flat and then join.
In so doing, after first row finishes with back post hdc (dc)
turn,
ch as written and
work (WS facing) next row starting with fphdc (fpdc).
With beginning yarn tail, stitch a seam to close the area and work in the round thereafter.

Recommendation # 3
If using this yarn or one that has a marked halo, work dc’s instead of hdc’s. Your fabric will still be full and warm.

None of the above recommendations will take away from your finished project aesthetically nor functionally.