I have been reading a lot of complaints about sparklies on the Black Diamond screens, people tend to buy them for light walls and daytime use, with the money you have at your disposal i'm surprised you didn't go for a Seymour, they're not all acoustically transparent but the constant area masking is a huge thing to have.
You'll be upgrading next year to Dolby Atmos or Auro 3D if you haven't already.
I've already prepped for Atmos. That was part of the planning. We have shadowboxes above for overheads, though they aren't mounted because B&W didn't have any that really will go there at the moment. I'm not going to rush that under the equipment is right.
You know, on the screen we looked at a lot of options. This room also exists as a panic & storm safety room.. behind that screen is a 10" concrete wall. The doors is a steel trap door/etc. When I talked to B&W about customizing speakers for the room, I liked the CT8, but I needed them inverted with some minor changes. It was easier to get that done then try to worry about knocking out a concrete wall to put something behind a screen
I chose the Diamond Zero Edge Black because when I projected true 4K content, I didn't find any screen in the same category. You do have to take time to get the projector to really use it correctly, but once it's setup just right I get an image like nothing I've seen.. it is sharper and without being overwhelming brighter and more enjoyable than any LED TV I've seen.
I looked at Stewart and other screens.. everything had pros & cons. But the DZE really, really worked out for me. Since I'm constantly flipping from 1.85 to 2.39 to 2.40, I wanted that to be open motorized and ready rather than have to deal with re-sheeting. It's been flawless for me.