My grow-outs currently go from bowls to autowaterers (nipples) at around 6 weeks having never seen a water nipple in their life. For the first day I put a bowl under the nipple and fill it twice a day from the nipple, so they can see water comes out of it. Second day I fill it once from the nipple. Third day I remove the bowl and make sure to push the plunger on the nipple a few times a day so that a drop or two of water sits on the end of the nipple. By the end of the third day they are normally all using it fine. I haven't lost a rabbit to this method yet...but of course I keep a close eye on them. Though generally once one figures it out they all do. My first litter that I've had in a cage with autowaterers are 3 weeks old and all starting to use the nipples, though I did put a bowl in there just in case.
As for separating the two does....just separate them, nothing special about that.
