continuous insulation above grade interior face block wall climate zone 4A existing building – GreenBuildingAdvisor

Climate zone 4A — 1960’s construction basement walkout – above grade exterior walls

I have a 2 wythe masonry wall in my walk-out basement. the outer wythe is full brick and inner wythe is CMU. I have no water-infiltration issues.  

I have air sealed the interior face of block wall with Henry 17MR which gives me a continuous 14 perm air barrier. [theoretically]

I am contemplating installing a layer of continuous insulation on the interior face of the CMU. likely surplus from commercial roofing — poly-iso [foil faced or not]; a rigid rockwool; or new formulation XPS.  

interior cladding is an open question. i may get fancy since i don’t want to add studs — may use vertical hat channel with densglas or densdeck or use a panel system. have not decided.  

what is the minimum R-value of insulation that i would see benefit?

are there any panel systems that come to mind that would work good?