Sheet Metal Gages

I’m designing an oversize coping -- what gage should I use?
I know my gage in stainless steel, but what would that be in copper?
I know my thickness as a gage, but what is the equivalent mil thickness?

These types of questions can be quickly answered by referring to this PDF:
Sheet Metal Gauges per Uses.

The first page is compiled from SMACNA. The second page shows the approximate correlation between different types of metal, sizing metrics, and uses.