Zone 4A 160sf Shed -realistic insulation for size – GreenBuildingAdvisor

Building the wife a 160 sf office shed, 2:12 monoslope/shed roof ventilated. Due to the foundation requirements around tree roots and a power line, it will be elevated on helical piles.

Looking at a manual loadcalc my heating/cooling btu’s are in the middle/lower third of a 6k btu inverter Mitsubushi minisplit with R30 (really R32 planned 5″ of polyiso) floor and ceiling w/ R15 mineral wool bat walls.

Floor to be built akin to this: https://www.greenbuildingadvisor.com/article/insulate-raised-floor

Full air barrier w/ Tyvek/henrys on walls, taped floor seams, interior walls and ceiling with MemBrain. Metal roof w/ small thermal break underlayment over high heat ice & water, directly on sheating. Roof is north facing and largely shaded by giant sequoia.

Overall is my insulation balanced to the smallest size unit attainable? I don’t want it to have moisture issues as typically we have noticably humid Spring, Fall and Winter in the PNW. Would I also benefit from a 10 cfm ERV?