I prefer to find another top from another truck. It can be a different truck, but better if it is the same kind and year. Cut out most of the center and use the skin from the other top so all your welds are on the edges, keeps the body work mostly on the edge and not the center. Quarter the top like above making one side front or rear longer to cover the missing gap. Both front to back and side to side. This may sound goofy but if you never did one try it first on and old junk yard truck. Better to blow a few bucks on a junker than on your pride and joy.