Another small-breasted, small-nippled over-supply/ OAL momma here. No HG, no celiac, no thyroid issues, though.
Pre-nursing pumping and block-feeding helped a bit when V was tiny (I didn't know about sage until this thread- will def keep in mind for #2!), though not enough for her to comfort-suck (thank God she took a paci), and now, at 7.5 months, I still get engorged in the morning and shoot across the room/ soak through my shirts, but by some grace of God, have not had blocked ducts that I couldn't clear up on my own in a day, and no mastitis. She's been able to comfort-suck since about 4 months or so, which is nice.
Apparently OS and OAL run in my family- my mom and sister both had the same issues, though only my sister had serious morning sickness (not quite HG), none of us have gluten issues, though my sister for sure had post-partum thyroid issues (dunno about my mom.)