I know I'm late on this, but I just found this thread. If you must have an ammeter and don't like running that kind of power to the gauge, use a remote shunt. Aircraft have been doing it since they had charging systems. I remember seeing some in the VDO catalog several years back (it was for a 150 or 160 amp meter though). If you keep the regulator housing one could easily be hidden in there. You wire the shunt just like you would an ammeter, then run wires to the actual ammeter. this does require removing the shunt from the ammeter itself (most I've seen are just a piece of wire between the posts) which if internal could require a trip to an instrument shop.
