Checking my ticket (which has PARTIAL VIEW stamped on it), I was sat in G17 in the Orchestra. From what I remember, part of the top left is obscured, but apart from a few of Biggley's scenes on a platform (I could see him fine, mainly the scenery surrounding him was a bit of a blurb), I saw the whole show very clearly.
Anyway, that was just my seat, one out of a possible 50-100. I believe the boxes are also part of the rush policy.
Everything in life...is only for now.