hi dan. thanks for the information and clarification. since i'm new to large format, i'm only kinda pretty sure that i understand the implications of your analysis.
i guess if i were to ask in more layman's terms, what i want to know is how the 6x7 roll film back is going to influence my choice of focal length when choosing a lens (i was using the medium format analogy because i am familiar with what the 80mm lens on my contax 645 looks like when i go to compose).
thanks, again, for your input.