Chris,
I think the problem (if there is a problem) is related to your photographic experience. The application of a camera to a telescope and the resulting image has nothing to do with crop factors etc.
What different sized chips affect is the field of view recorded, not the "magnification" of the image within the field.
The focal length (usually fixed) for the telescope determines the plate scale of the image (arc sec/ pixel).
Try CCDCalc as a means of getting your head around the issue. It allows you to input various sensors and view the probable outcome with sample images of well known astronomical objects.
http://new-astronomy-ccdcalc.software.informer.com/1.5/
Hope this helps.