Thanks Stevie, great info!
Just so I understand you correctly about the radiator, do you mean that the grille hanging between the aircleaners should be removed? Just want to check so I understand what area should be modified.
From what I understand (I asked in the Allied DG a few days ago, see link below) the cover on the rear of the turret should indeed be there as long as it is not a very early M4A1 (76), just as you said above.
Regarding the hull ventilator cover between the hatches, see my reply below to Jeremy.
Hmm, sounds like you're really into Shermans!