I've always been a 20-minute-per-pound-at-300 gal, myself, probably because that's the way my mama did it. I find if you glaze, that generally keeps the ham from drying out. I also tent it with foil loosely during cooking, and baste.

USDA says 140F is sufficient. You don't want to dry it out. Here is the fact sheet and cooking times. For bone in smoked, cook 15 minutes per pound at 325F.
http://www.fsis.usda.gov/factsheets/ham/index.asp#9