Hi J.,
I didn't have the anterior placenta, but I did have two boys in posterior presentation. Even so, they were two very different labors! I had to be induced with both pregnancies. In each case, I had started dilating, but never got into a good pattern of contractions on my own.
In both labors/deliveries, my boys were "sunny side up" - but it was only in the first case that I had back labor. I truly believe that positioning can make a big difference (try hands & knees w/back labor). In addition, having a little oxygen helped me breathe through the contractions better. It's hard to truly know what you're going to want until you're there. Your body's and your baby's reaction to all of it may steer your intentions in a different direction, too.
Best of luck for you and your little one!