looking for help

[MJS]

Let me know what you think on the following shots. Both shot on Nikon D70. These were just test shots to check on light placement. F8, 1/320 second. Auto white balance. Two Alien Bee 1600 into 48" silver umbrellas. Keylight about 8 feet up on 45 degrees to subject. Fill light at F4. Test one fill was elevated at about 7 feet, just to right of camera position. Test two had light same position but on eyelevel with subject. There was a small pocket strobe slaved to hit the background. The actual subjects will be wearing black formal wear while playing their instruments. All repro will be done in B/W.

1. What about light positioning.
2. Can I go down to 5.6 and still keep enough DOF, so the wrinkles are soft on the BG
3. What would you suggest for a background exposure, next time I'll use a manual strobe that I can dial up or down.
4. Do you think this type of shot needs a hairlight.

Thanks for the help. I begin shooting on Monday and need to make the changes.