Hi,
When I first joined I too kept a few snakes in one large enclosure and it took a good while for people to talk me into trying one snake one cage.
I will never go back to multiple BP's in the same enclosure again.
Since you are going to have to use at least two enclosures in order to get your new snake up to size and to stand a chance at having even basic quarantine proceedures I really would suggest you try adding another and keeping all the animals seperate.
This also means you can feed in their enclosure to try that out at the same time.
Once they have settled into their new routines I don't think you will go back either.
Also if you cut the food down to small rats every 7 days you should find that ( in conjunction with the new housing situation ) their feeding record improves dramatically - I know mine did.
You also have a lot more ability to observe each animal to check for problems and have a great deal more control about the whole breeding thing.
dr del