Well to be honest, I've never hit with either of the Aerogels you're interested in.
But I do know that the AG 200 (16x19) thats out in Europe right now isn't much like the AG 200 out here in America, or so I've been told. From what I've heard, from a friend in England, the other version of the 200 has much less control than the 18x20, its much thicker (beam), and feels stiff (I didn't know what that meant considering its a 200, its open string pattern).
And about the 100, unless you're in Europe you're gonna have to pay some big $ to get it shipped out to wherever you are, and thats at least an extra 20 Pounds ( if you buy from UK) which is a lot of money in my books.
Sorry I can't tell you much more than that
Hope this helps