Exp fastener metal roof, underlayment over batten?

I have roof condition that’s it appreciate any wisdom on.  From the inside out: cathedral ceiling with R30 Rockwool batts, zip sheathing, 2in of XPS, and horizontal 1×4 battens, waiting… I have roof condition that’s it appreciate any wisdom on.  From the inside out: cathedral ceiling with R30 Rockwool batts, zip sheathing, 2in of XPS, and horizontal 1×4 battens, waiting…Read MoreGreenBuildingAdvisor