I pray everyone in the MidWest and along the East Coast are warm and dry. And for my friends on the West Coast, I'm coming to visit you.
After my last session I could really use your help. The lighting was the most difficult I've encounted so far. But, I know there must have been a way that I could have used the existing light better. So, I'd like to ask the collective wisdom of OSP and ask for your help.
Main shooting area without flash

Main shooting area with flash

(This group shot contains a vignette and was shot using my Lightsphere)

(Although I like this shot, especially as a b/w image, I don't like the dark shadow in the upper left-hand corner caused by the flood light shinning against the back wall)

Addtional challenges - the space was too small for the group I was photographing. There was a larger adjacent area (as seen below) but it contained a long mirror and less lighting that could fill the faces without a flash. Plus, the entire area was lit using industrial flourescent lights.

(It worked for these types of images - ISO 1600 no flash)

(This is the main wall used for the majority of the portraits that evening)

(And, it worked really well - ISO 800, iTTL, SB-600, Lightsphere)

My gear:
Nikon D70
18-70mm f/3.5-4.5 ("kit" lens)
Nikon SB-600 set to iTTL
Lightsphere (I also used the built-in diffuser as it seemed to light the room better)
ISO 800 & ISO 1600
All handheld
Didn't mean to write a book, but as you can see I really want to understand this so that I can really "nail" the shot for my next client. Thank you in advance for your help and I look forward to reading your responses. Did I ask for help already?