Was able to get the insulation done. I decided not to take the perforated ceiling down but I was able to slide Reflectix in over the one inch bat insulation that was above the ceiling. Then I used four 1 1/2” wide 3/8” plywood strips to make the ribs. That made it possible to install another 1 1/2 of Polypro. 3” of blue Dow styrofoam in the walls.