Clecos are one of the coolest inventions ever, and do work good on mocking up pieces and holding them for glue to dry. They also won't distort the panel like a screw that is in too tight. But for the price screws are hard to beat. Make sure that after you are done you pull all the screws out and fill the holes with glue, don't weld the holes it will heat the surrounding glue too much and it will let go. Also when you are finished put a light coat of Evercoat "Kitty Hair" or equal product around the entire glued area, if there are and voids or air pockets in the glue this will stop moisture from coming through unlike normal plastic body filler. good luck with your install, gluing is one of the slickest methods i've tried so far.