Rip two peak assembly boards, 74 x 7 3/16 and 73 1/4 x 7 3/16, for either roof side, matching the rafter angles. Also cut four braces from 2-by-4s, 7 1/2 x 3 7/16, matching the angle of the rafter peaks. Set each brace evenly against the peaks of each of the four middle rafters (opposite the hinged side); drill a hole for a four-inch hex-head screw through both brace and rafter, and secure the screw with a flat washer and hex-wing nut. Caulk over the screws after tightening. Screw the peak boards to the braces using 2 1/2-inch deck screws; you'll need to bevel the edges where the boards meet and then caulk the lengthwise seam.