A changing speed of light was the main issue in the thread I started months ago. Many other constants and particularly rest mass would be affected as well.
Yupperoonies. Everything interacts with everything else. And nobody's come up with a model that includes such changes and isn't refuted by existing observations. Setterfield's been trying for literally decades and has failed. Take a look at
Re: Flood dating discrepancies, which may or may not be out-of-date but illustrates the kind of issues that come up. See also
Critique of Some New Setterfield Material.
The bottom line is, unless you're a physicist and extremely familiar with the relevant issues and interactions, you're not going to come up with a workable model.
Apart from that, I would like to know what atomic mechanism is responsible for the missing mass that shows up as kinetic energy in driving away the daughter products?
Typically that's a subject in graduate-level quantum mechanics. Take a look at
Modern Nuclear Chemistry if you want some fairly heavy reading.