This is an interesting conflagration of ideas, so I finally broke down and looked up van Flandern and his Lorentz relativity (LR) versus GR's mass-energy equivalence (MEE) and its Lorentz invariance.
"Michelson tried in vain to measure a motion relative to Maxwell's hypothetical medium. Empty space doesn't have a point zero to refer to. It is just distances between locations. You are right, this is no new insight. The only "fix" point in universe is the permanently moving relative to the agreed Christian timescale point now between past and future. Einstein's Poincaré synchronization was aptly called by Van Flandern a de-synchronization. The now can be shifted at will only on the level of abstract time, not in reality. Georgina seems to have understood this. Einstein, Steve, and Tom perhaps didn't."
Fortunately, the rabbit hole was not very deep and in fact, van Flandern has a very good point.
Now GR and LR both use exactly the same math as van Flandern so nicely describes...so it is not surprising that both GR and LR are fully consistent with MEE. The difference between LR and GR is simply that LR assumes an absolute frame, say the CMB, and GR assumes no absolute frame except the walls of the universe and the event horizons of all the black holes.
"Empty space doesn't have a point zero...{except for} the permanently moving relative to the agreed Christian timescale point {as} now between past and future."
It is true that the western (i.e. Christian) calendar begins its year zero near the time of Rome's subjugation of Judea, a significant event that nevertheless is just a convenient zero year and other calendars use other significant events as convenient zero years. The most convenient zero year for science, though, is the CMB at z = 1091. Science knows the CMB very precisely and anyone in the universe who measures the same CMB time as we do we imagine as coresident in the universe.
The further GR description of a universe where gravity action is due to gravitational distortion of space works quite well for a large number of predictions. Gravity distortion of space occurs as a result of the norms of matter and time and so the gravity distortion of space determines a single path or future for each object ahead of action. As a result, the GR universe does not account for the many possible futures of quantum action very well at all.
Although there is agreement between GR and LR about the existence of both rest and moving frames, LR presumes a single absolute rest frame, an aether as it were, through which the rest of the universes moves in its many moving frames. The interesting complement in quantum action to the two time dimensions of rest and moving frames is the trimal notion of a ground state, an excited state, and an excitation that couples the ground and excited states.
Instead of the dual universe of relativity as rest and moving frames, the quantum universe is a trimal of ground state, excited state, and excitation. Now we can simply connect the logic of these two universes by supposing that the rest and moving frames of GR or LR represent the ground and excited states and some excitation by some third object, say a photon, then completes the description of action.
What the principles of GR and LR both lack is that very important third principle of the trimal; the exchange of matter that connects the rest and moving frames. Since macroscopic objects moving in time under gravity depend mostly on the norms of matter and time, GR and LR work quite well up to certain diffeomorphic limits (I love that word diffeomorphic...it sounds so differomorphic). All action in GR follows from gravity distortion of space, not from matter exchange.
Although all force is due to matter exchange, gravity force is mainly due to pairs of exchanges, i.e., neutral matter changes and not charge matter exchanges. Thus matter and time norms describe gravity force very well with spatial distortion without the exchange of amplitudes and phases that is the underlying quantum reality.