Yeti cooler like lid details for my 48′ tall multigenerational ICF home – GreenBuildingAdvisor

I wanted to get some feedback on my roof details that are kind of a take off of the article that Martin did a few years back about “Installing Rigid Foam above Roof Sheathing. Except in my case the sheathing and the foam are one and the same because I am using a product that embeds metal studs into the 5.5″ of EPS foam. One metal stud on both sides so they are thermally broken.  Basically it is a skip sheathing method with Sharkskin Ultra SA on top of the foam panels and then a mechanically seamed standing seam metal roof that is at a .5″/12” pitch on a mono slope roof.

So couple of questions.  I plan on treating the bottom steel stud in the foam panel like the bottom sheathing in Martin’s article which means in my climate I can only have 49% of the insulation of the 5.5″ of EPS foam below that point to avoid condensation issues. Part of that insulation will be 3″ EPS foam panels that go in the opposite direction as the 5.5″ foam panels.  These will be sitting on top of the I-Joists.  Both the 3″EPS and the I-joists are inside my ICF walls and the 5.5″ EPS will be on top of the ICF walls and will overhang the ICF walls.  Hence the Yeti cooler like lid.   So my question is does this make sense to treat the bottom metal stud as if it was wood sheathing?

Also I will have either rock wool or fiberglass batts in the cavity of the i-joists to make up the rest of the insulation to almost match the EPS foam in the 5.5″ panels.  And I will be using the Intelo smart vapor barrier to hopefully control the humidity in that cavity because I will have a serious stack effect going on given the fact that I have 5 levels in this 48′ tall multigenerational home.

I will also strap the ceiling under the I-joists so that I have no penetrations from lights.  And one other detail is I will have zero penetrations through my roof.

Any thoughts on what I might be missing.

One thing I learned today is that when I am connecting my metal roof panels that before I seam them I need to use a butyl sealant.

Any other thoughts for me to consider as I try and make this roof/lid as airtight/watertight and manage the vapor in a way to decrease issues for my posterity over the next 500 years?