Well, let's see...

You take a stopwatch, calibrate it severely so it's accurate, then take another stopwatch, do the same, then active and stop both at precisely the same time after enough time has lapsed to be useful.

How fast is time?

Yep - you got it!

Precisely one second per second!!!

Ever heard of a "dimensionless quantity," before? Bottom line, it means "you can't measure time."

By the way, "perspectives of God" approach won't wash because it assumes it's outside/beyond the universe against which all measures are based.

In short, the nature of the universe itself sets the measurement criteria. You can't escape their, regardless of whether your universe is the size of a super-universe football or a planet. It's the universe itself which establishes the measurement criteria, not the supra-universe in which it might reside.