0 is correct.
Setting the zoom sensitivities to 1 is correct if the hipfire FOV is the same for Apex and BFV (in this example). If the hipfire FOV is different, the zoom sensitivities will adjust for this, so scopes with the same FOV have the exact same sensitivity between the games.
The result will be the same for each scope you configure, so technically there's no difference. But it's a lot easier to just set the coefficient to 0 and zoomsensitivityall to 0.888877. This way you can leave all the scopes at 1.