So 4" where the foam vent is 6" where it isn't.
I already bought 6.5" r19 insulation this was a leak that is fixed.
It is only doe this space you see is the 6" smushed going to be too smushed?

 

You can always slice with a knife halfway through the insulation and then tear part of the insulation away to conform to the shape of the baffle if its too tight to fit. Compressed insulation loses it's r-value so you are better off not smashing it in there too tight.

 

Pushing 6" in against the baffle would risk crushing the baffle. 4" of fg insulation in NH is not very much and the baffle shown is not as wide as it should be. Do as "X" suggests, cut away some of the fg so it will fit better. I also see strapping which will create an air gap above the drywall. Find some 3/4" rigid foam board and cut to fit between the strapping to add a touch of insulation and eliminate the air gap. If space allows, cover everything with more rigid, then vapor barrier and drywall. The extra rigid might eliminate the need for the vb depending upon what room this is.

Bud

 

Thanks I will do and cut it back a bit there