Thanks on the congrats

My a-times ARE scarily big!!! It's getting easier, but when I first started, it was SO hard to play with her for so long. I was used to an hour awake, two hours sleep!! Now it's just a matter of keeping her occupied for 3 hours, which is really hard even though she's pretty good at entertaining herself for some of that time. But also, keep in mind, it took me over a month to get here and I'm still working on it, so you'll have time to adjust to it. That's where I had a lot of problem - I am not a patient person and I wanted the solution to happen overnight and it just doesn't work that way.
Her bedtime has really been the only thing that has always been pretty much under control. I think it's important to have a consistent BT for the LO, but what motivates me is my evening time and the knowledge that it will end at a specific time

Her BT hasn't been affected by pushing her atimes, but mostly I think b/c if she needs 3 naps, I monitor the last nap very closely and wake her up at a time when it will work with BT. For example, FOREVER she was ending her last nap at 2ish and her BT was no earlier than 6, but ideally b/t 615 and 630 (I have now pushed it back to 7ish so she'll sleep later in the mornings). Earlier than 6 and it was guaranteed to be a nap, not bedtime. So first I tried splitting that 4 hours in half, but that didn't work b/c she wasn't tired enough to go down. So I'd wait until 2.5-3 hours (depending on her) and put her down and monitor exactly what time she fell asleep. Then I'd wake her up exactly 20 minutes later. Any more and she'd fight BT more than usual. Sometimes I'd push her BT back 20 or 30 minutes but usually she was ready to go to bed at her normal time anyway, even with the super short atime after the 20 min nap. But now that we have extended atimes and thus her naps have extended, they are also more evenly distributed throughout the day. So my day looks like this: up 3 hrs, down 1-2 hrs, up 3-3:15, down 45-1, up 3-315 so her BT is right on track. It took a lot of waking her up from CNs to get there b/c I don't let her go 4 hours w/o a CN if I can help it.
You are probably already doing this, but I also think it's very important to log EVERYTHING. That way you can see patterns specific to your LO and see what works for him and what doesn't. I finally got so frustrated trying to figure out atimes and adjust for them that I went and bought a wrisother bumch and synchronized all my clocks. I don't adjust atimes anymore - and that is when we made our real breakthrough, btw - but I log everything to the minute. I hear her peep in the morning, I look at my watch and remember the time even though I don't go get her right away. I log what time I put her down and what time she actually falls asleep. I log how much I feed her and at what times. Knowing how long it takes her to fall asleep is important - if it takes 20 minutes, I probably put her down a bit too early (this is why her afternoon atime is 315 rather than 3). I've also recently started calculating totals: total day sleep, total night sleep, and how many ounces. Also how many times she cries out or wakes up at night. I didn't expect to get much info this way, but I actually realized that when she sleeps more than 3 hours during the day, she cries out a lot at night and sleeps fitfully. This is really valuable info to me b/c now I know if I want a good night, I better not let her oversleep during the day, tempting as it may be!!
Just remember that it takes a long time. And sometimes it will seem like you are getting nowhere. Or you'll have a good day followed by 3 days of bad naps again. You just gotta keep working till you get that first nap sorted out and just do what you need to to get through the rest of the day. And also, a mistake I made was to try to make jumps too soon... what worked for me was to make a jump, get a long nap, and then stick with that atime until the nap shrunk back down to 45 minutes for at least two days in a row. Those two days are hard b/c you know the rest of the day is messed up, but you gotta make sure he's really ready for the next jump.
I'm sorry, I talk a lot and I feel like I'm not very clear b/c I over explain. So I'll summarize what worked for me and what in your shoes I would try. I don't want to sound like I'm telling you this is the only way to do it or whatever, I know you'll of course only do the things that make sense to you and work for you, and hopefully other people will also give you input too and you can combine all the pieces that work. But here's what worked for me:
Work on extending the first atime by 15 minutes every two days until you get a long nap or a 30 minute OT nap. If you get that, go back to the previous 15 minute increment for a few days. All other atimes should be 2.5h until you feel that needs to be increased just a bit or unless you get OT naps for two or three days in a row with that. If you get a long stretch between last nap and BT, try a CN but don't let him sleep too long depending on how long that stretch is. What worked for me is sticking to this plan no matter when Ellen woke... long nap or short, her atimes were always the same. That's what made all the difference in the world even though it was really hard to do, especially at first.
Eloys - I think you are right about the A times last time. And I would say that in my experience getting the A time right BEFORE you start sleep training makes all the difference.
I absolutely agree with this. I am a wimp too when it comes to her crying, and I was determined to do sleep training, but never really could stick it out. That's why to me atimes are so important. If you can get the atimes right, the sleeping really just follows. Or at least it makes it a lot easier. I only do sleep training (pu/pd or whatever) when she's super duper OT and I know she just has to sleep. If I have any doubt whatsoever as to whether or not she's tired enough, I just don't have the balls to do it. I'm a serious wimp. In your shoes, I def try to get his atimes right before trying to get him to fall asleep in his cot by himself... he'll fall asleep much easier if he's sufficiently tired.
Anyway, sorry for talking your ear off... hope some of it is helpful!!