1962 Pontiac Catalina 2 dr Htop 389V8 AT

[Catalinaman44]

I have a 62 Catalina that I'm going to install front disc brakes on, with 15 mags.
I see some cars with 8" power boosters others with 11" ones.
My question is do I need the 11" or will 8" be fine?
I'll install AC later, when I can find one?
I'm 78, so hot rodding in out of pics.
This is a true Survivor Auto, plan on keeping as such. Just enjoy it.
Live in South Carolina, if that will matter? heat & humidity daily?

 

[melsg5]

Is the 8" dual diaphragm and the 11" single, if so same boost effect.