You may want to do some research on compatible materials for "gluing" the roof skins to the luan which eliminates roof rumble while traveling and on windy days. Roof rumble = rippling/waving of roofing material in areas not glued down.
I've found metal roof material that is glued down doesn't shrink with cold and swell with heat as a non glued metal roof material. This constant movement is hard on the material in areas that are fastened permanently to the roof ie (roof vents/vent jacks/etc).
We all have seen RV trailers going down the highway with a rubber roof flapping just behind the front cap (ballooning). Aluminum roofing material reacts much the same when not glued down properly.
