I'm considering getting a Packard shutter, but as I have never actually seen one, I'm not sure what size to get or how to mount it. I would rather mount it to the camera rather than front mount it to my lenses.

Obviously, the opening would have to be as large as the diameter of my largest lens, but what about the size of the shutter itself?

For instance, my lens diameter is 2-1/2" - my lens board is 6" - but a 2-1/2 inch packard shutter is only 4-3/4" square - not large enough to fit behind the lens board. Does one mount the shutter to a larger board which is then mounted inside the camera, or does one have to get a shutter large enough to fit behind the lens board regardless of how large the opening is?

Thanks in advance,