Full-length portrait of conductor- help!

Having it a little further away could even it out more... light falls off by the inverse square rule. When the light source is close, the fall off will be greater.

Perhaps, but I feel 306 and 329 could have benefited from a little fill on the right (his left) side, just a fill/bounce card for his face.

Other things to think about. Why f/8? Did you need the background in perfect sharpness? If you opened up, it might have given you more power to work with. The SB-800 was not powerful enough at full power, going to f/5.6 would let you drop all the lights except the SB-800 by a stop, making the SB-800 appear brighter. I'm mostly saying this as a thinking exercise.