Heres a neat way to make those full screen crossahairs u somtimes see, sorry guys no pics:-).
Ok, any widht and height is fine, like 400 by 400. Make the backgropund black in this case. Grab the line tool, make a line going vertical and one going horizontil. Make the horizontil line line2 and vertical line line1, target both. Then go into the scene script. enter this code