DD2 was posterior... there was a HUGE difference in the labors between her and DD1 who was in the optimal position. DD1 was a 7hr labor, DD2 was 21 hours, most of which was with no dilation since she wasn't pressing on my cervix enough due to her position.
DD2's birth story is
HERE.
I would highly recommend trying to get her to move before going into labor. Everyone talks about back labor with a posterior baby, and it's true... but what I wasn't prepared for was the thigh labor... I seriously felt more in the tops of my legs... I couldn't walk or even move through a contraction. And the combination of contractions and a baby wiggling through them trying to turn was brutal. I made it through though, so it's possible... but I will definitely be doing everything possible prior to labor next time to make sure the baby isn't posterior.
ETA: Wanted to add, for those who don't read my birth story... DD was born at home with no meds... so it's definitely possible, even though it does hurt more.