Yes, if you change the size of the ridings, you would have to decrease the number of ridings so that they would increase in size. Obviously, that would make representing the wishes of your constituencies more difficult. However, don't forget that the proportional seats in my model.... At least I would suggest that they be distributed according to regional criteria so that they would all represent different regions and provinces. Those seats could take on responsibilities of local representation just as easily, I think, as people who are representing individual constituencies. It wouldn't be quite as direct a link, but if the work were done to make sure they did represent local constituencies, it could happen.
This is an aspect of the model that I haven't really worked on very much. I have been more concerned about the mathematical distribution of seats and so forth, rigging a system that will be proportional, or quasi-proportional, and have all the other benefits I mentioned. Your question could also be addressed to anyone who supports MMP, for example, because in MMP half the seats are also proportional. How is it done in Germany? How is it done in New Zealand? These are not new questions there.