Can I assume you do have an bungelow style attic space, where part of the ceiling walls are slanted?
I consulted a friend on an bungalow attic remodel. He did most of what I suggested, and he gave it an B+. Could have been an A if he did my full plan.
Here is the short of it: you need to seal the living space from the non-living space. This was done by creating an air channel between each stud with Cayno using It would be best if you could remove the thermal short circuit where interior drywall is nailed directly to the same stud that the outside sheathing is nailed to. Thermal short circuits reduce whole wall R values by 30% with 16 inch centers, 24-26% with 24 inch centers. Where the room ceiling is angled is where the expensive insulation is.
Ill comment more later, my infected workstation is gonna be re-staged.