Landscape Coords vs UVs

I know if I have a landscape that is 1000 x 1000 resolution I can set the Landscape Coords node to 1000 and get 1 to 1 scaling.

If I didn’t use a Landscape Coords and instead a V3, what would the value be? I’m trying to match a texture to the terrain and not use Landscape Coords.

Still trying to get this to work. The idea is I have a color map overlay for my terrain. I think overlay that same map on the grass using world coordinates, so the grass picks up some of the color.

Now I’ve setup a world aligned texture but it seems to have run into a scale limit, when I reach that limit, the texture funks out.

Anyone have ideas on this?