Thickness of platinum foil for enameling

Platimun foil: Does anyone know what kind of thickness I should be
looking for? I want to use a thin backing of platinum (foil) to do
plique-a-jour. Apparently, this is the easiest method as the foil can
be peeled after firing the first layer of enamel and reused endlessly
(as long as I take good care of it). Found a lot of info about it but
nobody mentions anything about the thickness of the foil.

Lucie