Projecting onto live performers (musicians, dancers etc)

Dear Tagtool community:

I’m planning to do some live projection with a music group in late November and will either project behind them with a ceiling mounted projector tilted down or onto them directly and then onto the screen. Do you have any experience of this, and I’m wondering what is the best setup/angle so as to not blind the musicians?

Also, is a black or white background better to project on in such circumstances? I did a test and white seemed much more vibrant.

Any advice appreciated. Thank you! Karen