Post Frame Insulation

I am in the process of building my 40x56x16 post frame garage. I originally planned on spraying foam right to the metal roof and sides for insulation but I am second guessing that as the panels have raised ribs that shit behind the girts/perlins that could possibly not be filled in by foam. I am debating now whether I should put foam board insulation between the perlins and girts and then sheet over it (sheeting between the posts) and have foam prayed on the sheeting. It is lots of extra work, am I over thinking it? The foam boards would allow any moisture to drain out or dry out. Spray foam is the ultimate insulation but I do worry about rot over time.