Eric Flesch wrote:
(2) There is a migrating universal "constant" such that in earlier
epochs matter bent light more per kg than it does today.

and later

Heavens no, all I'm saying is that just as GR generalized SR, so can
GR be generalized into a larger frame where G (or some such) migrates.

In other words, you're effectively hypothesizing a time variation in the
Newtonian gravitational constant "big G".

There are quite good experimental bounds on the time variation of G.
See section 4 of
Jean-Philippe Uzan
"Varying Constants, Gravitation and Cosmology",
Living Reviews in Relativity 14 (2011), 2
http://relativity.livingreviews.org/...es/lrr-2011-2/
for a review.

Notably, this quotes a very tight lunar-laser-ranging bound:
J. G. Williams, S. G. Turyshev, and D. H. Boggs,
"Progress in Lunar Laser Ranging Tests of Relativistic Gravity",
Physical Review Letters, 93, 261101, (2004)
http://journals.aps.org/prl/abstract...Lett.93.261101
preprint at arXiv:gr-qc/0411113
These researchers find
(dG/dt)/G = (4 +/- 9) e-13/year
i.e., (quoting from the PRL paper)
"The $\dot{G}/G$ uncertainty is 83 times smaller than the inverse age
of the Universe, $t_0 = 13.4$ Gyr"

One can of course imagine a theory in which G varies a lot at some past
time, but then the G(t) curve flattens out so that dG/dt is small at
present times, but this seems somewhat ad-hoc.

--
-- "Jonathan Thornburg [remove -animal to reply]"
Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
"There was of course no way of knowing whether you were being watched
at any given moment. How often, or on what system, the Thought Police
plugged in on any individual wire was guesswork. It was even conceivable
that they watched everybody all the time." -- George Orwell, "1984"