Can't answer your first question but have had some experience with the lower price seating:
My husband and I sat in Dress Circle CC 37 and 39 ($40 plus fees) for Beautiful and were pleasantly surprised at the sight lines. Sound fine.
Ran into acquaintances that evening who had been sitting in the Lower Boxes ($20 plus fees) and they were also happy, very happy, with their experience.
So we tried the $20 Lower Box seats for Cabaret (Row F 51 and G 50...different sides of the theater as an experiment). These seats considered obstructed view (tickets stamped as such in big red letters), but we were both delighted with the sight lines (very minor limitations....a few times an entrance was not observed until the character moved toward center stage. Seconds, not minutes later). We found the sound to be perfect from those locations.
Tried Lower Boxes again, this time both on the left side of the theater, for Curious Incident. Definitely obstructed view at times; highly distorted angle at others. Our choice didn't work out well that night.
But we've discussed on a number of occasions over the years that we could pay dollar for a centrally located, highly desirable seat, only to have, perhaps, a "bobber and weaver" in front of us, a seat-kicker, talker, behind us. All have happened; can't predict that aspect.
Our conclusion is that, understandably, it depends a lot on the staging of a production, some luck re neighbors, and of course, personal criteria for a satisfying experience.
Sincere best wishes in selecting your vantage point.