In regards to shooting greens with waterfalls. How do you guys do it?

This is my 6 stop B+W filter:
http://www.flickr.com/photos/31194022@N00/6697896961/

And this is my 2 stop:
http://www.flickr.com/photos/31194022@N00/6697896815/

Do they seem right to you? Will Lee or Singh Ray be better or do you simply just go out with overcast days and shoot without the filter or maybe even shoot at very small apertures and accept diffraction?