Thus, a change in c would imply a change in the speed of propagation of waves in the electro-magnetic field and the weak field and the strong field. This would, in my opinion (none of this has been proven empirically.....it is indeed speculation on my part, but based strongly on a general knowledge of how physics works), result in a change of rate at which the strong field, weak field, and electro-magnetic field interact with each other.
How strong a general knowledge? If you couldn't prove it empirically, which you can't, then if you knew enough physics then you could prove it theoretically, which you haven't.
So if you can't do that then it's the sort of idea that might come to one in one's bath.