Good morning A.,
Isn't it crazy all the little details we have to think about when we have children???? Feed them, change them, make sure they're the right temperature, clean them and postion them so their heads don't become mis-shapen!! They say a womans work is never done........
What I did to position my children was to think of them like Lincoln Logs (crazy I know... but just keep reading!) You know how Lincoln Logs have a flat part on the bottom and then they are rounded on the sides?? When I would put my kids down for naps I would make a conscience decision to alternate between their left rounded side, the flat bottom, and the right rounded side. But don't just think of the head... you really have to position the whole body. For example, if it is the left sides turn to be slept on.. you need to use a small rolled up blanket, pillow, a small bag of rice in a sock.. anything that is going to raise and keep your daughters right hip and shoulder 2-3 inches off the sleeping surface so that the majority of her weight is on her left side. Then you do the same thing when it is the right sides turn. Put something under her left shoulder and hip that will keep them 2-3 inches off her mattress so that a majority of her weight is on her right side.
Since she is showing signs of getting more than enough time/weight on the back of her head... you might want to try just alternating between sleeping between her right and left sides to balance things out.
It might be worth a try! This is the technique that I have used for all 4 of my kids.. and I am REALLY not one to brag, but I have actually had nurses compliment my babies on their nice round heads. My personal belief is that the trick is in solidly positioning the whole body... not just the head. I hope this helps!
Good Luck!
Peace,
B.