There are a limited number of skeleton and zombie parts, so I would think that ten cultists, five skeletons, and five zombies would work. If you're referring to weaponry, it doesn't matter since there is only one cultist entry in the bestiary, with no weapon specific rules. They don't have a ranged attack, so arming them with bows or crossbows would only be aesthetic. There was some gaming magazine that had an article by Joe which included rules for skeleton archers, however, but I don't know the details of that.