I've had CNX2 for some years now and have never used the Size/Resolution dialogue. If I have an image I deem suitable for a print, regardless the size, I've always cropped for better composition if needed and size desired, sharpened if needed, etc. and have the resolution set at 300 dpi. I guess I'm trying to understand the necessity of the Size/Resolution fix.
My goal in life is to be the person my dog already thinks I am.
Children are for people who can't have dogs. ~Author Unknown