The Monster takes away some homeruns, the damn 406 club or whatever they want to call it takes away even more IMO. Superimposing a spray chart won't give you actual homeruns unfortunately.
In 1969, Rico hit 55% at home (22). In 1978, Rice had 61% at home (28). In 2009, only 42% of Bay's homers were at Fenway (15). In 2018, only 41% of Betts' homers were at Fenway (13).
Wade Boggs was a huge opponent of the 406 club back in the 80's after the construction and stated that the wind patters changed how the ball carried.