I think you are on the right track. Even the small size at 3600x2400 would provide all the resolution required for an 8x10 inch print (at 300 ppi). I would select Fine quality, but Medium quality would be adequate for most people and get teh file size down to something more manageable.
The benefit of the D600 or D800 over earlier cameras 12 megapixel images is in downsizing. With downsizing you will have all the benefits of high resolution downsized to a small size. That means noise levels will be minimal and you will see little pixelation compared to earlier cameras.
One thing to watch for is you might get some moire in resizing that is not present in the RAW file or a JPEG that is not resized.