that was actually the first one i did where i did cut the outline out, but you just drill a small hole with a jewlery drill bit than a small wire box saw
That is neat.
I found a place that sells jewelers saws but am not sure of sizes.
Are they like shotgun sizes?
This place has them from # 1 to # 4/0 .
What diameter in inches (or centimeters) do those numbers mean?
A 12 gage wire is maybe .093 inches while a 12 gage shotgun is maybe .750 inches.
12 gage sheet metal may be something else, I don't know.
I get confused by terms specific to the industry and not easily related to physical standards.