It is a nice very idea for an experiment, but I don't think that radioactive decay would be an accurate enough 'clock' to use because generally with these types of measurements very small differences in time are detected - generally atomic clocks are used to measure the time in these experiments. With the radioactive decay process it is random decay and there will always be some uncetainty in the activity of the sample after the experiment.
I also wonder whether the centrifuge is equivalent to a gravitational field.