Wow. I'm glad I just started reading this group. What a helpful bunch here!
I'll the the original poster would never have thought about looking it up.

Not everything that you and I might take for granted is common knowledge among
some of the new builders - or even somewhat experienced ones. And sometimes
those of us that have been doing "it" for a score+ years forget that not
everybody knows the basics.

To answer the original post - the smaller the drill bit the faster you
can/should turn it.

In my experience:

for sheet metal work (drilling #30 holes) the fastest air drill you can buy is
none too fast.

A sharp split point bit and an accurate center-punch help too.