IMO, it is a total waste of time to go through that. It is perfectly fine to use one neutral for a circuit as long as it was done before the new code. If we changed everything every time they changed the code, we would be constantly rewiring our homes. Shared neutrals was done for 100 years and almost all homes wired a few years ago are like that, My house is like that and I am an electrician.
Yes, you can get shocked in some small circumstances by sharing a neutral if you are working on the dead circuit, but it is very un likely. After working as an electrician for fifty years I can barely remember getting shocked like that. Maybe 3 or 4 times in all those years. You are not supposed to be working on your wiring anyway if you are not sure what you are doing.
You can use that double pole breaker if you want, but it is overkill.
Yes, you can get shocked in some small circumstances by sharing a neutral if you are working on the dead circuit, but it is very un likely. After working as an electrician for fifty years I can barely remember getting shocked like that. Maybe 3 or 4 times in all those years. You are not supposed to be working on your wiring anyway if you are not sure what you are doing.
You can use that double pole breaker if you want, but it is overkill.