It's great to have friends who have such nice glass.
The setup: Light shining from behind the subject through a large diffuser and around white poster board. The background (poster board) is lit from below by a lamp with a diffuser attached, not because the light needed diffusing but because the diffuser reduces the amount of light by about 1 to 1 1/2 stops. The subjects are on a mirror tabletop. Gobos very close to the lens on the left and right sides blocked the light that would have created awful flare.