Nitrous plumbing A1A...??..

One of the points that Mike brought up was the bar orientation going through the plate.. blue being nitrous and red being fuel and I told him that both had blue fittings... He said just to make sure the bottom bar was fuel.. (something I never thought of)..
So first thing I want to do tomorrow is take the plates outside and blow carb cleaner in each port and determine which wire goes to which side?? I assume carb cleaner can't be too harsh as it would be the same as gas or anything else that's going to go by These bars 99% of the time?...