@User: The pitch is what you want, although to get the space between blocks you'd have to calculate (pitch - block width). It appears that I never finished writing the "width" and "height" command options (sorry!). "pitch" does both width and height at the same time, so do "array pitch" first to get the values of both, and then plug back in the value of the one you don't want to change along with the new value for the one you do want to change.