How often you need to prewash depends on the kind of fabric your dipaers are. If they're unbleached they should probably be washed in hot with a smidge of detergent about 4-6 times. They'll keep getting more absorbent for a while after that but they should be plenty useable by then. Bamboo is probably about the same thing whereas bleached (white) diapers probably only need maybe 2-3 at most (the bleaching process helps remove a lot of the oils which is what impedes absorbency). I've seen some people say that you should dry in between but frankly I just can't see how that helps. The whole point is to remove the natural oils in the fabric and drying just doesn't do that...

As for washing 8-10 diapers at a time this is for prewashing only, not when you're washing dirty diapers. And yes, I'd say it's fairly important. If you wash too many at a time for the first few washes your lint filter will be overwhelmed and you'll get little lint balls everywhere. I speak from experience unfortunetly...

I definetly wouldn't recomend rinsing an exclusively breastfed baby's poopy diapers. As long as they're exclusively breastfed their poop is water soluble (hence will rinse away in a pre-rinse before washing) and hardly stinks (hence won't severely stink up your pail). Once baby is on a significant amount of formula or solids then all bets are off but until then I say why complicate your life... You'll almost surely get those super bright, almost neon, breastfed baby poop stains (which you'd still likely have even if you rinsed) but just lay them in the sun for a few hours and they'll totally disappear! It's hard to believe until you've seen it for yourself but sunlight truly works wonders on stains, especially breastfed poop stains.

HTH,
Karen.