The articles referenced do not claim that variations have actually been observed/measured. The cited articles propose hypothetical models only.
Some very small variations have been observed, but I cannot now cite the reference because it was a few years ago that I read something about this. They involved experiments in which light beams were passing from one medium to anot ...[text shortened]... o impact whatsoever on the size or the age of the universe in any macroscopically observable manner.
I will post what I watched to bring this up, but I'd have to warn you its at the end
and this guy is going to say some controversial things long before you get there.
He went back into some published journals where they were measuring and
publishing the data, there were changes some large going in both directions.
He went to a place where they studied constants and talked to the guy in charge
and discussed this with him. He acknowledged the changes and said it wasn't
something they liked so they made changes to take care of it. If you want to see
it the link is below. I can only image the link will start a few conversations if it is
Rupert Sheldrake The Science Delusion (just so you know what to except)