Its a good idea to, instead of one screw to hold the top hatch on, that you put two in the corners. placing them directly into the top of the triangle stock. Chances of having one loose screw let the hatch lift and jettison is greater than one out of two, or as I did, after being told by an experienced builder, just left the one in the center and put the two on the corners, thus having three! (no, it won't start affecting your CG unless you use half a dozen........)