I know its nice to have ones own tools, but have you considered
buying the disks all ready cut? here in the UK, we have the largest
precious metal supplies called Cookson Metals. They were formally
Johnson Matthey. they will supply you with disks or squares in any
thickness in any size from 5mm in dia increasing by 1 mm up to 400mm
in dia. You may find an equivalent supplier in the USA. Depends on
how many you need at any one time. cost? the same as sheet, and yoce
no waste to sell back at a loss.