One thing I noticed while reviewing our footage is that silk seems to be a good starting point for overhead diffusion. The Opal created kind of a blotchy diffusion and still showed the problems of under eye shadows. Silk seems to keep a bit of the highlights on cheek bones, but the under eye shadows are almost gone. Muslin was a bit flat for my taste. I like to have a bit of light shaping a person's face.
Another thing I learned is that back light reflectors need to be much closer than I originally thought, not only for light strength, but for modeling the shoulders and hair on our model. I think in our case it was about 5 feet back from her. That provided the correct amount of "halo" effect.
I hope you find these tips useful. As always please call the shop if you have questions.
A big thanks goes out to our beautiful model Sofiya for frying in the SoCal sun with us today. It was a sweat bath out there and Sofiya was a true trooper.