Being an electrician, I'll tell you that a greenlee knockout is by far the cleanest. It can dimple the sheet metal though. As far as 1/16" it might be asking alot of a KO set.
Your next option is a good old fashion hole saw and some cutting oil. Which is what I recommend. Keep a file handy to remove rough edges.
If you can find a carbide tooth hole saw that looks something like this.
http://www.grainger.com/product/WESTWARD-Hole-Saw-6EXP3?s_pp=false It would be ideal. They make super clean cuts. Unfortunately the bigger they are, the more expesive they are.
So, the good old fashion hole saw is probably the best. You can get them anywhere, and they're cheap. So if you burn one up, no biggee.
I've used them on 1/4 plate for adding strength to a mezinine. Whe had to run 4" cunduit into the bottom of switch gear. USE LOTS OF CUTTING OIL AND TAKE YOUR TIME!
