I had the "which side is up" question too. I called Van's. The lower spar splice angle has one inch legs. The doubler has holes spaced 1/2 inch from one edge and 3/8 inch from the other edge (reference Figure 6). The 1/2 spaced holes go down which should put your holes near the center of the 1 inch leg of the lower splice angle. The upper angle has 3/4 inch legs so the side of the doubler with the holes spaced 3/8 inch from the edge goes up and should put your holes near the center of the 3/4 inch leg of the upper angle. One other easy way to tell is the that the edge of the doubler with the dished out relief at the bend line goes up. Hope this helps.