Yeah, I saw that Lefty recommends that (50% leader step-down). I love that guy -- I'll take whatever he says and just assume that he's correct
Hand tied leaders are pretty easy actually - I tied a few this evening using the perfection loop, and 2 seaguar knots. They feel pretty strong, and I always put some "umphf" into them to make sure they are tied well. I didn't want to end up tying 5 or more pieces of mono together because I don't like complexity, so I'll try the 3 part leader and see how it casts. If it works well, I'll probably just stick with it.
I also took Lefty's advice and taught myself to tie the non-slip mono loop knot. It's actually pretty easy to tie and seems strong.