This is a tricky one because there are so many options.
If you come in from the side then you have some deep shadow, especially on the faces, which might look good but if there's no spill onto the background (or the background is black) then it may be a bit too moody.
You could light pretty much from the camera position but raised a foot or two above. If you're shooting centrally then this will give you maximum coverage from the flash but position it too high and you might create some hefty shadows under the eyebrows.
You could light from a low position but it might look a bit 'hammer house of horrors' if you're uplighting.
Do you have any reflectors that you could call on to bounce a bit of light back in?
I'd ask Garry Edwards - he knows his stuff in this respect