I am quite short and even for me the leg room in this part of the amphitheatre is only just enough. I find the problem is aggravated when your neighbour is average, tall (or dare I say it fat) and keeps trying to steal some of my space. Its worth remembering that the front row of the amphitheatre although the view is great has less room and that is why it is cheaper in the centre block.
I would go for the seats in row C if only because they are nearer the aisle and quicker to get in and out of if you have to catch a train an the end of the show.