Dark acoustic ceiling tile recommendation?

I'd like to put a dark colored acoustic ceiling tile grid in my home theater room. Black or dark gray tiles. I'm wondering if I could get a recommendation for a tile that works well and looks good? I'm unclear on how important the NRC and CAC values are, and if it is worthwhile to pay more for higher values or thicker tiles? Ideally I'd like to stop some of the sound from leaving the room and going into the space above, but I'm not sure how much the higher CAC tiles would actually help with this, considering the room has had no special "room within a room" treatment, and there are still HVAC ducts and all that. So is it worth paying more for a higher CAC value? Thanks!