Smoking a cooked ham on a drum

Any tips on smoking a ham on a drum smoker? I have 2 hams that are each about 5 pounds. I figured I will keep the smoker around 275 and wondered how long it may take to get them to temp of around 140? I have heard from others that they only get their ham to just over 100 degrees and they say how juicy and tender it is. Will 140 over cook the ham? As far as the glaze, when should I start adding it and how often should I add more?

At a cooking temperature of 300F it takes approx. 17 min./lb to reach 100F. Many different methods to glaze. One is to glaze first, wrap in foil tightly and put in oven/drum/on grill, bring up to IT of 100F, then pull back foil or remove upper foil if if it has glaze on it if it's sugar based.(it will burn and smoke at higher temp.) Glaze again and raise temp. to 425F,cook for 30 min., glaze and cook another 20 min. Remove from heat source cover and rest for20-30 min. Serve. Or, for simplicity, apply glaze during the last 10 min. of cook time. A pre-cooked ham has been cooked to a minimum of 145F. USDA serving temp. is 140F. The ham I'm cooking today will most likely end up around 120-130F IT.