Sleeping arrangements

Ok, I need some more advice from you moms of multiples out there...Jack will be right around 23 months when baby number #2 comes along in November, and I'm trying to decide what to do about sleeping arrangements for him and the baby since I've heard I don't want to try and transition him to a bed with a young baby at the same time.

We bought Jack one of the convertible cribs, and so far he's still happily sleeping away in it. I think the answer would be more obvious to me if he was scaling the crib walls every night, but he's quite content to sleep in it right now. I'm hesitant to switch him to a bed too early, because a lot of moms have mentioned that naps tend to dwindle once a child can get in and out of bed him or herself. I love nap time!

Right now I'm leaning towards keeping him in the crib and worrying about the transition after the baby comes, unless he shows signs of being ready for a different bed here in the next few months. I suppose we could buy another convertible crib for baby number #2, that way I don't have to worry about moving Jack out of his too soon. The one we have now has held up really well and was a pretty good deal, so money wise it's an option if we could find a similarly priced crib.

When did you transition your child to a toddler or twin bed? Any tips on how to do it?

Thanks!