what size fuel line for nitrous setup?

Yes, I will go a little over what I currently need, because I want it to be upgradeable later, should I decide to go big block, big juice etc. That was my intention from the start, to not have to re-do stuff later... make the car upgradable. I just wasn't sure what was completely overkill (like just flat out wouldn't work) and so on.

Thanks again.