Review/Alter my plans to insulate dad’s shop – GreenBuildingAdvisor

I have a pole shed (shop) without sheathing on exterior under steel siding.  I’m planning to remove the vinyl faced MBI (condensation blanket) underneath exterior girts (where it’s pinched between girts & steel siding w/ fiberglass, R-3 or R-4 against steel).  Plan to not remove steel siding and install:                                                         

                            – tyvek against inside poles & girts (I realize                                                                        not perfect, but best can do)

                             -taped osb or plywood over that to inside of girts

                              -fill w/ cellulose 

                               -osb or sheeting over that.

My 2 questions:     1.)  do I use plywood, osb, or foam board on inside of girts

                                  2.) do I put a vapor barrier on the inside of wall either 

                                         under interior osb or painted on sheetrock etc.

I know it’s not the best, but if I spend for the best I would loose money on my farm, so doing what I can with what I have.  I read a lot of articles on the web and this site so I know the downsides (is what it is).

thank you in advance (all opinions welcome),

Matthew Currier

location is northern Illinois zone 5, Henry County