Been there man. Hung a pantry cabinet last year where the wall bowed in about a quarter inch right behind the middle stile and I spent way too long fighting the hinges instead of just furring it out. Now I run a straight edge across the wall in three spots before anything goes up, top middle and bottom, and if I see light under it I deal with that first. Takes two minutes and saves hours of dumb fiddling. That 3/8 over 30 inches would've jumped right out at you too. Live and learn, we all eat that one once.

Testing at home is overrated. A leak might not even show up on your carpet because temps and humidity are totally different from a cold mountain night, so you get a false sense of security and skip the real check. You also waste a whole night on the floor when you could just fill the pad, let it sit a few hours, and look for any soft spots. Half the time the valve is fine and the problem was you not closing it all the way at 3am in the dark. Plus some pads only leak when they get cold and the material shrinks, which your living room will never copy. Learn how your gear actually fails in the field instead of babying it at home.