Well, seeing as many states have adopted the CARB filler, getting NATO carns can be a PITA. The blitz cans are usually crap since they have leaking issues when you put a spout on. The large O-ring doesn't help much at all. Also, because of their design the rolled seam on the bottom tends to leak if not taken care of. The NATO cans with their vertical welded seam tend to hold up a lot better.
I want some gas cans to mount up top on a rack so they gravity will help the fuel down to the tank. Personally, I wouldn't want them inside since you will need to strap them down somehow. Any leaks will also be a problem as well.
Strange that a state would make it illegal to mount a can on the outside as most commercial trucks have externally mounted tanks still. Do you have the actual code?