Great subject matter. I'm not a good monitor, so I have no comments on the B&W conversion. One quibble though: the images are huge! Try to keep the longest side below 800 pixels so most people can see the entire image on their screen. Much bigger and most viewers (1024x1280 seems typical) won't be able to see the whole thing...
As far as black and white conversions, I'd say you're on the right track. The trick, as far as I'm concerned, is getting enough contrast so your shot isn't a bunch of middle grays, but not so much contrast that you lose highlight or shadow details.
