Ceiling and attic space

I am bulding a studio in the upstairs of a barn. The space is approx. 50' by 32'.(see image below). The roof is a gable roof along the long axis with a shed dormer over the control room and a perpendicular gable dormer over the "Recording A" room. This creates an attic space above the front of the control room and the recording spaces as well as the entrance area. the walls between the rooms are double 2x4 studed walls with 2 layers of drywall on the outer faces. I plan to use t layers of 5/8" drywall on all surfaces including the ceiling and use mineral wool in the stud and joist cavities. Would there be much benifit to using RC-2 on the ceiling of the two recording rooms or the control room. there is no one else in the building and not much traffic noise. My main concern is isolation between the rooms. Thanks for the replies LBC