I am a dalight dealer, have your installer get samples. Dalight has a book with all there screen materals on it and you can hold them up to the wall and look at what the image looks like. I would look at something with a gray tint if you have any ambiant light blacks are your issue if it looks good with ambiant light it will only look better at night. I do like the cinima vision 1.1 gain HC, that use to be my goto dalite screen for installs like yours. The snap AV screen is nice but the materal is not totally smooth, he can also get a sample they are free, I don't think that would hold up well under true HD or 4k projectors. But he has sceen the room so ymmv with my advice.
Note: Any posts are of my personal opinions and not to reflect upon any business.