Thanks for all of your encouragement and advice. I think I may see how the 4 hour routine will work with him - I thought he may be needing it just because he is already so big and thriving, nevermind that he's also a very effecient eater! I figure, if sometimes, before he's 4 months, he wants to eat after 3 hours, then I'll feed him, and if he can do 3.5 or 4 hours then we'll do that - I can't see there being anything wrong with following his lead in terms of 3-4 hour routine until he settles fully into 4... today he woke up at 6:45 am after going to bed at 8pm and waking only at 3am for a feeding (1/2 hour including burp and going back to sleep in his crib) - I nervously let him have a catnap again from 5:30-6:15 last night (fearful that he wouldn't go to bed or that it would interrupt his night sleep because it did last week, resulting in over 2 hours of trying to put him down to bed) but bedtime obviously went very smoothly.
Right now he has been sleeping since 8:15am, so he was awake for 1 1/2 hours, including feeding (though he was awake in his crib about 15 minutes before I got him up to feed him) - right now it is almost 10am so he is approaching the 2 hour mark. I'm going to have to wake him up at 2 hours because I have to go out to an appointment today at 11am and he has a doctor's appointment at 2pm which means if he sleeps much past 2 hours at next nap time, we're going to have to wake him then, too. However, after that, I'll see how long he actually sleeps - I think I will make sure he just doesn't go much past 2.5 hours!
Really, this is such a dream - I can't believe how hopeless I felt just 3 weeks ago!
Did any of you have to help baby through the 45 minute transition? I'm having to do that most naps and it takes about 20 minutes for him to be fully off to dreamland again enough for me to leave - is this what you found? When did you start leaving them to do it on their own? How can you tell that they are ready and don't need your help?
I'll keep you posted on whether or not just letting him sleep longer works out!