The underside of the batwing was broved from the upper front corner to a fan like pattern down the batwing. The fiberglass mat is laid perpendicular to the grooving to hold that arch. Before mat was laid the underside was sanded and acetoned. After setting up the re-arched batwing, it looked and felt correct to the body. There is still the reattachment of the framing, side piece and finishing the underside to get back to where I started.