So how could you conclude that there couldnt be enough concentration of matter in the universe to shrink or expand the universe signifigantly?

Our earth is a small gravitational well, our sun is a slightly larger gravitational well, the center of our galaxy ( or whatever causes the stars to spin around the center ) is a larger gravitational well. How much gravity are we talking about? From the vacuum of space if we looked at our planet from a system outside of the gravitational effects of the sun or of the galaxy as a whole, how big is the gravity well that effects a rock thrown on the surface of our moon? grant it the strongest percieved force is from the moon itself. But everything on the moon including the rock is being
effected by the earth and everything on the earth and its satelite ( like the moon and the rock on it ) are being effected by the sun and the sun, the earth, the moon the rock are effected by our galaxy. Removing all these gravitational effects. How compressed would time-space be relative to the rock on the moon or to the surface of the earth.