I would add that for a CRT native resolution as one would think of it in regards to truely 'native' could be considered a 'range' of resolutions that the monitor is known and certified to suport, and recommend as operating within. Whereas you can run outside of those parameters (usually at some risk to your monitor) it's not seen as the optimal balance for the scan line refresh. What they usually call 'native' for CRt I'd simply refer to as 'default', because I just don't consider a CRT as having just ONE native resolution so much as a min a max, and everything in between that fits within a 'native range'.
I like to force 1440x1080 on my 16x12 17" because it looks best to me and increases the refresh slightly, however it's withing the range of the horizontal scan rate. It's not a listed resolution, it's not a driver enabled resolution, but it works fine when forced.