It would be good if mammon locations and times are in dnwiki.
Thanks for your suggestion. ;)
Their behavior are written in wiki already. Spawning interval/place and 7s period length can be changed/differ in servers so I don't think I will mention about time but about spawning interval, I think they stay at a place for at least 20 mins (which is enough long to catch him.)
Spawn place at the beginning of seal week or after reseting server was always same (blacksmith at Witch, merchant at Disciples) but I'm not sure at this present.
Please feel free to edit. It's Wiki site.