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I would thro in checking the shappell's, when I did my research last year they used a heavier duty fabric.
Shappell doesn't make one in the size he is looking for. He is looking at twin hubs. The ones where you can park a car in.
Clam has made mistakes in the past, but they do hub shelters better than anyone. I've owned several and they are far superior in hub reliability than Eskimo in my experience hands down.