question for the contractors out there, R11 vs R13 insulation

[fishinpox]

First off start by removing all that attic decking , if you want it decked fir up the ceiling joists to make a deeper cavity for r 38 then deck over it. Add some power vents to your roof . This is where you will notice your biggest difference . I'm assuming you are leaving the exterior veener ( brick , stucco, siding etc) and sheating? You could seal along every stud cavity with a foam or caulk then get a blown fiberglass in the stud bays .