BabaJ

Run over your points in a 'for' loop in detail mode.

Why do you say it's the wrong size?
No one can tell by just a screen shot since if the bottom of your grid(y-axis) is not even with world grid,
it will make it seem like a different length visually because of the perspective.

Post your hip.

I'm not experienced in COPs....but could you not do something like feed a separate color channel to 3 tile patter nodes then recombine after?