That's what I thought but I figured I'd check first to be sure it wasn't a new thing and I wasn't going to go making a fool out of myself by making a bad assumption! ;-)

Ok, so for your questions... I don't know of any one-size wool covers at all so I can't help you there. I don't imagine they're very common, whether velcro or not, as even one-size PUL covers are hard to find (I've only ever heard of one). But that doesn't mean it doesn't exist... That would probably be awfully bulky though, many people find wool to already be bulkier than PUL so the folding necessary with a one-size cover would make that even worse.

For doublers I don't think that using wool will influence that at all. Wool does absorb a lot for a water resistant material (most waterproof or water resistant materials don't absorb at all) but it pales in comparison to the absorbancy of diaper fabrics like cotton, bamboo or hemp. I doubt it would ever be significant enough to alter how much absorbancy you need inside the diaper.

I will say that most people only find they need doublers for nighttime or maybe really long naps. You'll get the occasional person with a really heavy wetting older baby/toddler that will need them when using the One-Size (it's a smidge thinner than the Sandy's so a little less absorbant than the large Sandy's) but that's more the exception. Most likely you'll only need doublers when your little one stops pooping at night so you can start thinking about extending the time between changes to minimize nighttime disruptions.

I'll also second aavt's suggestion of fleece liners. Super easy to make yourself, just as effective as commercial stay-dry liners and way cheaper! Also if you're looking for the ultimate in poopy diaper cleanup, maybe consider a diaper sprayer. It hooks up to your toilet and you can just spray poop off the diaper! Of course, if you plan on breastfeeding, the poopy diapers of an exclusively breastfed baby can just be thrown into the pail as is. Exclusively breastfed baby poop is water-soluble so a pre-rinse before washing will rinse it all away and it hardly stinks so it won't cause major odors in your pail. Once baby is on solids or formula then all bets are off, but in the meantime it's a nice luxury!

Karen.