Bobeetie,
You have probably made your choice, but here is what I did. I have the Piano 3100. After speaking with the Dalite rep, was steered toward the Videospectra fabric (based on the lumens of the piano). Screen size 60 x 80, model B, video format. I drop it down to the desired length.
Immediately disliked the PQ. The material was too reflective in some movies the whites were washed out and due to the reflective material, the picture appeared pixelated at 1.5X distance. I tried to convince myself and my family but we all agreed that my wall was better. After contacting my dealer and dalite, they offered to replace with the Matte white screen material. I received the new sceen a few days back, and the difference is remarkable. The image is very film-like and colors truer. I did many side by sides of these 2 screens and would recommend the matte white. After this experience, I am not sure I would go for any screen with a higher gain. Hope this information helps you.
-mahesh-