Centrifugal... is really the opposite of gravity and reacts to gravity as a reactive force. In general Centrifugal force is really reactive.

Centripetal is more in line with Gravity, since gravity is "center seeking".

To answer your question about the clock, I'm not qualified.

I wonder if they could put a clock in one of the "g-force" emulators they use for Military pilots for a few hours and see.