AAV's do what they say on the tin, they admit air. What they dont do is let positive pressure
out, so it doesn't matter where you site them, it still works the same. Drains need to breathe, hence why Building Regs state the drainage system must be ventilated, and Builders put at least one vent stack on each property. Seen numerous instances of AAV's being used to replace vented stacks, and then problems ensuing. See here:
Foul smell in bathroom since Durgo valve installed | DIYnot Forums
My advice is based on years of experience in and around drains, but ultimately it's your call.