I used the end chopping method only briefly, and quickly decided it ain't so great. Now I always chop down at the wood, and frequently hear that I'm 'doing it all wrong'!
I find that when chopping down from the top, it is not critical to remove all of your knots. Knots can be easily chopped through (though with great care) from above, but cannot be split through from the ends.
If I ever find the time to work on my timbers here soon, maybe I will try and catalog some of my techniques. My style I am calling 'South Germanic', but really I don't know exactly where it actually comes from.