These are the current rules for size limits in Hell.
Guests are allowed 10% - 110% and no higher.
Demons can be 10% - 140% but i recommend being over 110 so that you are larger then mortals
Thanes are to me 140% - 160% Thanes should try to be large and almost godlike in appearance to show their demigod status and power gained from the Master.
Size limits are in place to limit lag in the room and to give benefits to members over non-members.