I imagine that a professional, such as David Manley could do a better job

Obviously (I would think), a trained naval architect who is also a naval history enthusiast, such as David Manley, could probably do a better job of doing a general design. I suspect that the sort of data that is really needed to do a good job might not exist. I have some hope that "ship's covers" might be obtained that would provide much of what is needed to analyze classic Dreadnought designs, so that we might be able to do a better job in our design work. The "Anatomy of a Ship" books would seem to be another good source of data.