I shot a green screen shoot yesterday for a TV commercial. We approached this slightly differently than the usual as we decide to shoot with the Epic camera mounted at 90 degrees shooting 5K HD in a 16:9 aspect ratio.
By setting up this way it meant that then we would shoot the talent head to toe and just wide enough to accommodate any hand movements for the whole shoot. Because of the 5K resolution of the Epic camera combined with the added resolution boost by shooting with the camera mounted at 90 degrees meant all the reframing could be done in post with no loss of quality. The finished TVC will have shots ranging from close ups to very wide shots where the talent will be about a quarter of the screen height.
This all enabled us to shoot very efficiently without sacrificing quality.
So on your next greenscreen shoot think about mounting your camera at 90 degrees.