Mills was a L-HW. the answer to this question is found in these match ups. Hagler v Woodcock (twice) Hagler v Lesnivich X2 Hagler v Maxim Hagler v HW Okek Hagler v Len Harvey Hagler v Lloyd Marshall and other Top bigger fighters. now from my ring side seat Hagler loses definitively to the HWs, and he has no easy time against the smaller fighters either, maybe pulling off a victory on points ocassionally, MAYBE. Mills was too big, strong and durable he would beat Hagler more than not!