I can't answer this from first-hand experience, as I'm going myself for the first time in June. However, I did extensive research, and I'd say the answers to your questions are as follows:
First, if you want to go in August, what are you reading this for? Get on the phone, NOW. Seriously, they book quick. I made our June 7 ressies in early Feb, and they were almost booked.
As for there being "good" seats left....from what eveyone told me (I had the same concern), if you define "good seats" as being front and center, you're probably out of luck for August. On the other hand, I've been told there is no 'bad' seat in the place. It's one of those wondeful architectural designs that affords good views from everywhere. And the cast, supposedly, works throughout the room to make sure everyone keeps involved. They even take folks out of the balcony to particpate.
Pat