I have an idea that explains Galaxy Rotation rates without requiring Dark Matter.
The URL of my short paper explaining the idea is here:
Great, so you can formulate this 'space-time density' and show how it is equivalent to GR?
This is an analogy for GR. And I am not sure I follow what you are saying - variable spacing of coordinates?
All classical field theories are geometric. The usual way of understanding the gravitational field is as a metric on space-time; but there are other ways of understanding this.
We don't see how his interpretation really relates to the mathematics.