To follow up on what ScoutDad said, the "E" was set to a known scale based on the blueprints and other "official" data. All other ships are scaled to match using a lot of "That Looks About Right " (T'Lar) discussion on the ADB board. There are a couple that I felt were "wrong", but I got out-voted. For the most part, however, everyone is very happy with the results.