If you go with the metal carport and want to close it in at times yet still be able to open it, there are several options. If you look at how they do it on greenhouses, they just lift the skirt. I haven't been able to find tyvek house wrap that isn't printed with some trade names on it, but if that doesn't bother you, you could use it and maybe turn it inside out. I would drive in a bunch of T-bar fence posts just inside the vertical supports with enough of a gap between them to roll up the tyvek. That way the tyvek is trapped between the supports and the posts when there isn't a wood stack there. If you choose to use plywood, run two long horizontal strips, hinged at the top so they open like awnings. That way you can open them up a bit and still have protection from a sudden rain. The triangular gable end top sections I would hinge on the bottom and open inward. Doors I would put in the center of both gable ends and I'd keep a center aisle open for access and for air, stacking the wood the same direction as the ridgeline.