Where and how to splice aluminum

Changed my mind and am now thinking about a grasshopper profile ten foot long. Rough claculation is that my roof skin would be 12 foot 8 inchs. Have priced 10 foot long aluminum, will check around for longer. Kind of thinking of starting at hatch with ten foot sheet and splicing at front. Two ideas come to mind. One is to bend a z hem (kind of like the way that rectangular ductwork is attached to each other) on the end of one piece(probably the shorter as it would be eaiser)and then flattening it. The other piece would then slip in this hem with some kind of silicone sealant. Hope this makes sense. The other would be a simple overlap with the raw edge covered by some sort of trim(insert molding without the one leg). They way I see it the first idea would have the advantage of still being able to float the skin as it wouldn't have screws as the second one would.
Thoughts, ideas, comments...
Thoughts, ideas, comments...