Hydro, interesting build you have going over there. I quite like the size of the room. A 25-foot long room is a good size. I think you mentioned earlier you are going for a 106" screen. I think you can get a larger screen size on that 12 feet wall. Have you thought about it. Insulate your roof well. I would recommend a false ceiling with sound-absorbing (the perforated kind) ceiling. With insulation above that. I would go with rockwool, provided it is easy to source where you live. Good for temperature and sound. Best of luck with the construction.
Thanks John,
The screen mentioned is from my old setup...I am planning for a much wider screen. Hoping to receive the insulating material today...will post updates.