Convert from fotmal [lead] to unze [Germany]

Unit Definition (fotmal [lead])
The fotmal is a traditional English unit of weight for lead. In medieval England the fotmal was equal to 70 "mercantile" pounds, which is equivalent to 72 avoirdupois pounds.

Unit Definition (unze [Germany])
The unze is a traditional German weight unit, corresponding to the English ounce. The unze equals 1/16 pfund. Although the pfund has been assimilated into the metric system (as 500 grams), the unze is effectively obsolete. It varied in size from about 28 to 35 grams. The word comes directly from the Latin uncia; the plural is unzen.