E.F.
I've used the BG 1, 2, and 3s and I think they are all too big for a newborn. (I think the difference is in the washing instructions, not the size). I agree with the other moms-- I would use mostly disposables for the first month or so, and prefolds with a Bummis cover when you are feeling ambitious. For the first 6 weeks, everything leaks, so do whatever you need to get through.
I did have some premie /xsmall happy heinies that worked the best for him when he was little. You could try diaperswappers.com to pick a few up, but honestly, I wouldn't invest in them unless you are super-green. 6 weeks of 'sposies is a hell of a lot better than 3 years!