I would go with the largest if I could, simply because of the force of wind-driven rain. But it's expensive. I had to buy mine fast, so I couldn't shop around. But I've since noticed that Harbor Freight online does have some sales that look pretty good.

I have no idea how much coverage you should have. Some is better than none, and if there is a widespread wind/rain problem, you might be hard put to find any at all.

Of course, you could collect enough to cover your entire home, and if you only needed a % of it, you could probably sell the rest to the neighbors! <img src="/images/graemlins/grin.gif" alt="" />

It's the same old question: how much is enough? How much is too much?

Sue