WOW! Thank you all so much for the really useful replies! I am getting exactly what I was hoping for, information and considerations that I had not thought of. I will likely be using this medium format system mainly for portrait photography, with an occasional still-life or landscape. I love the idea of using a Petzval or other non-OEM lens for unique results, that idea never occurred to me. Unfortunately I will need to build this system over the next 6 months or so, or save and research and purchase when the mostly complete package presents itself, if it does.
Until then, please tell me more about using Petzvals and other non-standard lenses on medium format bodies. How does one go about this and what resources are commonly available? Would I need to have custom machining done or are adapters fairly common etc?