I had first row in the mezzanine last summer for Bullets Over Broadway and the view was great. I was slightly off center, but no matter. Still a great view.
For Something Rotten I was about the same position in the mezzanine but back about 5 rows from my Bullets seat. Great view from there as well.
I used to be an orchestra guy, but now I prefer front of the mezzanine (or within a few rows back) if I can get it.
Someone else might have to give you information about the railing in the front of the mezzanine at the St. James. I'm about 6'3, so probably would have been able to see over it and didn't notice it. Can't remember too much about it.