I'm not sure about how much change there is. It's been awhile since I read the book. Increased length is easy, the question is, How much? Since the changes were for the "catapillar drive", I'd assume the increase would be in the Engineering Spaces, aft of the sail.
As for the increased width, I'd assume this was due more to the addition of sponsons, on either side of the hull, rather than an actual widening of the hull.
Whatever you do, good luck. And keep us up on your project. It sound quite interesting.
Mike K.