Lets put this to rest, The picture that you have show is about the set that the gasket should take, it doesnot radiate straight out. To promote a good seal the gasket lip must curl to the body sheet metal. When the windshield is closed this curl applies a slight pressure to the rubber gasket and the metal and prevents the water from wicking around a loose fitting seal and leaking. Also remember that the windshield frame is adjusted both upward, downward and inward or outward at the upper hinge to body mount. Incorrect adjustment there will also produce a leaky windshield gasket. Here is a shot of the preformed corners of the Drake gasket and it also has an inward curvature.
My take is to just reinstall the gasket that you have, remount the frame to the body and with the help of one of your buddies center the windshield frame in the opening and attach the hinge and regualtor. Fine tune the final fit adjustment, tighten and allow the gasket to form fit the body by a little direct sunlight heat and you should be ok.