I would use some plastic maybe about 1/2" wide and use that as Joiner/aligner. Using CA (epoxy won't stick) first rough up the surface with sand paper and stick the joiner to the insdide of one half first. Then use the the "ledge" created to glue the other half together. When dry lay a piece of Fiberglass cloth maybe 1" wide over seam on inside of cowl and soak in CA. Have done this a few times and creates a pretty strong cowl that will stand up well to everything but crashes. Good luck.