[bdery]

I'd like to see a bit of backlighting just to give them an edge to separate them from the backdrop. Even just a touch will work wonders.

Would you do that, say, with a low-power light source placed at 45° behind and to the side?

I personally like the "blending in the background" look, but it's ok to feel differently.

[SingingSabre]

That's where I would start. Up high, angled down to get a bit of hair lit up.