well to be honest most of the warbands have access to heavy armor, its just expensive. So what type of army do you like?? Chaos worshippers, Righteous Nuns, Ratmen, dwarves, etc.
Yea, buying the warband is fairly easy too, you can just pick up some fantasy mini's and convert them as needed or you can order the actual warband mini's in. The warbands run you about 45 bucks and model count varies on the team. I suggest going with a conversion team.
Usually we try to set the general time for between 5-6 and then are there till the store closes or people have to leave.