I have done this shot a few weeks ago and I would like your advice. I have decided to keep the BG with half blue on the left and half green on the right. To have a smooth transfer from the top right of his head and the BG, I have used the following set up 1/2500, f5, D300 with 200-400 at 400mm iso 400.
Sharpness is fantastic. I'd suggest cropping differently, e.g. putting the eyes close to the vertical 2/3 line. And the light seems to have been pretty harsh giving the shadow over the eye and the detail-lacking whites on the breast. JR