I have a post frame structure (40x72x16) to which I would like to add insulation. When it was originally built an r-9 insulation blanket was applied to the outside walls and trusses. It has taped seams and appears to be a lamination of a Mylar type material on the outside face, a white polyethylene(?) type material on the inside face, with a thin layer of fiberglass in between. There is a vapor barrier under  the slab with 2 inches of rigid foam insulation. The building is in very dry area (climate zone 5 front range of Colorado). Most of the large format insulating batts and roles that I’ve been able to find incorporate a vapor barrier or facing of some kind. My concern is that if I use one of these products I may be trapping moisture between the layers. Is that concern overblown given the relatively arid climate? If  I were to use an unfaced product it would at least have the theoretical opportunity to dry to the inside though I realize that’s not ideal either. The building will be used as a workshop and the only appreciable sources of interior moisture are a small bathroom and two sweaty neandrathals. Are there any good solutions here? Thanks