I also use 60% shade cloth. I wasn't able to source Aluminet last summer when I was building my greenhouse, but that's what I actually wanted! I'm so jealous that others have it. LOL
Unfortunately, I can't really comment on the Phrags, because I only keep a small number of them as an "experiment" in my greenhouse. It's a minimally heated set-up, I only heat it up enough to keep it from freezing. My Phrags stay indoors because our winters are too cold and the summers are too hot, just easier to keep them indoors. I do have a small number of "experiments" (i.e. Phrags that I keep in the greenhouse to test cold tolerance) but they aren't a good indicator for whether my light levels are okay.
I will say that with 60% shade, Cymbidiums and even higher light plants like my Dyckias and Passionflowers seem to be happy over the winter and I did leave the shade cloth on over this winter.