Rupert, the insight into your design and modelling process is fascinating! The fact that you design by hand, with an iteration process that requires patience, skill and vision, is simply amazing.
Yes, there are many modellers out there who are skillful with software that is capable of turning a 3D object into something that can be printed on flat paper or card, and then re-assembled back into a 3D object. But to have the talent to undertake this using eye and hand is astonishing!
The detail you capture using your, shall we say, 'traditional' methods is remarkable. It gives these wonderful models of ancient buildings an entirely appropriate old-fashioned patina. So, despite you saying that the large-sized drawings are necessary for your declining eyesight (hey, isn't the ageing process a real bummer?
), I think that even in the reduction back to print-production size, you have actually given the textures and details some grain that truly enhances the final product.
More power to your very capable elbow, Sir!