Thanks Paul,
My X and Y splines don't seem to work, is it because my surface isn't flat? It slopes upwards and appears to cut the array at a certain point.
Cracking presentation at SOA by the way, nice to see something a little different from behind the scenes!
Edit that, I didn't do it properly, I created an X and Y Spline. Not change the size as you suggested! It's too early for Railclone!