Personally I'd try using socks (multiple layers if needed) before using egg-crate foam. I would think eggcrate foam is too dense for our purposes, but I might be way off base on that since you're dealing w/ winds from a hurricane. I do think the shape matters in so far as if you put a square piece of foam on a 391 you'd end up attenuating sounds coming in at the 'corners' of the square more than the middle of the sides, if that makes any sense, although I don't really know how much it'll affect the sound. Also I would think that corners could actually end up causing wind noise rather than minimizing it if the wind were strong enough. OK, end of babbling. -Drew