We’ve been mounting the lights on the outside of the frame, which seems to give better results. The particles are tough because you have to move the lights much further apart to fix that issue. You could try blocking the light where it overlaps in front of the camera so you illuminate the target without illuminating the empty space in between.
Also, we’re working with a low light HD camera that is showing a lot of promise. Hopefully we’ll have something like that available in the future.