hell i cant seam to make the gride work i can ajust the seating and the only thing that changes is th size of the "cross hairs".ie size of the grid but all i ever get is cross hairs no grid?? also it notes too grid sizes one w/g20 next to it im asuming this means inch vs mm but im usint mm so sould i still put a gride size in this box?? thx chris