The mayor problem of having such a late wake up, is that the routine moves later, and you'll have a really later bedtime, and it will come a time when your LO will want to start waking up earlier, and ifshe has a later bedtime, 2well then she won't get all the sleep she needs. What i used to do when my DS would wake up hungry at 5-6ish am i would give him only just like you said, 1 or 2 oz to hold hom off till the 8am feed.
In Tracy's book, she does recommend that they shouldn't sleep more that 2hrs per nap, and when i changed my DS to a 4hr routine, he still wasn't ready for a 2hr Atime, so i did let him sleep 2.5hrs, and after 3 weeks of this when he DID started waking up at nigth chatting, 'cause he wasn't sleepy, due to too much daytime sleep, i had to extend his Atime to 2hrs, and everything fell into place again. But keep in mind that i changed him to a 4hr routine, for many reasons: First, he wasn't hungry at the 3hr mark; and second, his naps started to become a mess too. So my point, is that if your DD just isn't hungry at the 3hr mark, you can try the 4hr routine, and let her sleep a bit more, if she starts to wake up at nigth chatting, then you'll have to tweek the routine a bit more.
here's what my DS day used to look by then:
8:00 wake up and feed
9:10 wind down
9:20 sleep
12:00 feed
1:10 wind down
1:20 sleep
4:00 feed
4:10 wind down
4:20 sleep
7.00 bath and massage
7:30 bottle and book
8:00 bedtime
11pm dream feed
then he would wake up at 5-6ish am and i would only hold him of with just enough.