I just tried out the bags I got from Mylar Pro and the quart size will comfortably hold two round metal tins and two rectangular tins but only one larger style tall McClelland or C&D tin. Also a single big Solani tin will fit but only just barely. The gallon size will not hold four times as many tins as you might think but it's more like a doubling only with the exception of the tall tins of which four can fit.