I just acquired a Cirkut outfit and I'm a bit puzzled. The camera is a full plate (6 1/2 x 8 1/2) model while the Cirkut back seems to be an 8" -- at least it looks like an 8 1/2 in spool would fit. How do you tell for sure?

I'm sure I will have more questions as I delve into this piece of history.