It may not be logical or right, but I had some luck with night wakings by moving the bedtime later, to 8:30 or 9 with last feed at 8:30. My DS is 17wks. Then I treat any awakening before 7am as a night feed and start the day with a feed at 8am. (Even if he wakes up at 7) yes, it isn't EASY but it never seems to be with short naps.
I find that after the first wake up of the night he doesn't sleep as soundly and wakes more often. when i used to put him down around 7:30 he was up at 12, 2, 4, 6 if not more. since switching to 8:30 feed, 9pm asleep we are getting the first wake up around 2 or 3am and the next at 5 or 6.
Oh but I do have issues with the 4th nap, which I'd like him to take around 6-6:40, but often happens, if it happens at 7. Still goes down pretty easy at 9 though and usually is up for the day happy around 7:30.
He doesn't take a DF.We still go to bed when he does to make sure we get sleep, so these days I'm feeling pretty rested cause of the improved sleep. Although I can't wait to stay up and watch the news again someday!
We may just be in a good week, I find things change a lot so I try not to get too attached. My copy of Wonder Weeks is on the way and I'm hoping it will help me anticipate the bad weeks. Although I knew 12 weeks was coming and it still was miserable.