Its really dependent on what you are after. If you're just worried about fermentation, but don't plan on reusing the yeast, then I probably wouldn't even worry about dumping at all, at any point.
I feel that Martin's comments are more esoteric to his setup (small batch in a bigger conical) and I entirely understand his logic - though in his case, if I was looking to reuse the yeast, I would brew 5.5-6.5gal batches so that I could dump CB/Dead yeast and harvest a better colony but not worry about not being able to filla keg.
I think if you're looking at re-pitching, what I suggested will work well for your system. If you're not, then it probably doesn't really matter to dump at all.
I usually dump the trub after 24 hrs. My concern with dumping the trub is dropping out the highly flocculating yeast that settle first. That's why I try to remember to drop the trub as early as possible, preferably before high krausen.
I'm rather surprised at that- one in that its not that difficult to see the change from trub to yeast, and two from what I've read and heard from others (pros, experienced posters, etc) , you don't want the most highly floculating yeast - i.e. ones that settle before high krausen anyways - you want from the middle - if you were to consistently select the most flocculant, wouldn't you eventually have attenuation problems? Maybe you have other reasons for doing this, but I'm lost on the logic here.