The Enterprise J is supposed to be about 2 miles long. I'm not sure how long the G is, but I figure the H will be about the same width as the G, but longer, and the I will be about the same length as the H, but wider. Make sense? In relation to the J, the I will be about half as wide, but almost as long. I will scale the models from there (if and when I get to them, of course).