Nursing for longer periods isn't likely to translate into going longer between feedings. Breastfed babies tend to eat every 1-3 hours whether they nurse for 5 minutes or 30 minutes. If you've ever heard someone assert that babies "should" routinely go 3 or 4 hours between feedings, ignore them. That assertion is based on the feeding patterns of formula-fed, intensively scheduled babies. It's not a typical eating pattern for an infant.
Instead of trying to get your baby into a routine that makes life easy for your caregiver, I think I'd try to get your caregiver to feed your baby the way you do: responsively. Leave small bottles so she can feed baby frequently, instead of expecting baby to take large bottles infrequently.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"