[Poita (Peter)]

Ian, if you want to try out the QHY8, I have one I can loan you for a couple of weeks, PM me your details and I'll post it down.

Having been through a few cameras, I personally wouldn't go for anything smaller than the APS sized sensor, framing is such a pain with smaller chips, and having to do a 4 panel mosaic for some targets rather than getting them in a single shot is a massive benefit.
Especially with the 9.25".
Basically a QHY8 (any flavour) will give a similar FOV to your Nikon D80.

The first image shows the field of view of the QHY8 with a C9.25 and f6.3 reducer/corrector. The next rectangle in the image is the FOV of the 314L, and the smaller again rectangle is the FOV of the 314E.
The Second image is the Atik Vs the QHY8 again.