All great posts. I was originally contacted directly about this problem and urged Shaun to post on Cow. I’m sure he’s glad he did!
I really have litttle to add other than to agree totally with the use of shop fluorescents for the green screen, and paint them black to make them look professional. Oh, also, get the talent as far away from the screen as possible, which in your case is not very far. Some green light will probably bounce back and give green edges to your talent and props. Since you cannot use distance to your advantage, try light, diffused back lights with a slight warming gel such as 1/4 CTO to counter any green contamination. The intensity should be just enough to neutralize the green spill and not so hot as to make a hot edge, which will not key correctly.
Rick Wise
Cinematographer
San Francisco Bay Area
https://www.RickWiseDP.com