We do our hams or a head in a 20 litre pot. It seems smal compared to those sold on the market. They actually sell cauldrons that could not possibly be used in a house - the local speciality is Tete de Veau i.e big enough to take a cows head.
Fill on the stove and don't lift off until cool - then hands in and lift ( no spoon,ladel or kitchen tool seems to do the job of lifting hams etc out of the pot without spoiling the ham).