. We used those type of grids for this sort of puzzle in my "lets-find-an-excuse-to-get-the-annoyingly-smart-people-out-of-class-to-give-the-normal-people-a-break class" back in middle school. They were fun. I can't remember if they ever gave us anything that complex or not. Usually they only had 3 or four variables (but a whole lot less clues).
