The Plan

Thanks for all the suggestions - some were pretty dang close to my solution.  I must say that I really liked RJ's concept the best!  When I bought the materials, I also purchased end strips to correspond to the wave forms of the materials - foam inserts for the corrugated metal and plastic for the polycarbonate.  Tomorrow I am picking up some 2" flat stock steel 1/8" thick for the transition.  I loosely pieced together some parts to show the plan, using an aluminum strait edge in place of the steel flats.  I am lining up and  laying down the flat stock first (white primed to inhibit rust) and screwing through the foam into the peeks of the corrugated metal .  Then I will offset the plastic end pieces and screw down the polycarbonate into the flat stock.  The unions will overlap the corrugated metal about 4" at the top and on the south side.  Will add caulk as needed.  If none of this makes any sense - just wait and see how it all comes together. Sometimes it is hard to put into words the precise details in my noggin.