1967 Barracuda alternator upgrade question

The same amp gauge and same size wiring was found in those vehicles with the higher output alternators. If one should leave the lights on/kill the battery, or have any of several scenarios where the alternator does do all it can do, the wiring or the amp gauge may fail. Jumper from alt to battery detailed above is the simplest solution.
Of course the wipers, blower, a/c, everything in the cabin will would still be routed through the amp gauge. Your headlight relays have reduced the total draw there. So it comes down to what you want to do versus what you must do.
I did convert my alt gauge ( and serval others ) to a volts gauge but my reason has nothing to do with the amount of current going through it. I see gauges as on scene reporters. None of them should be able to interrupt the story they are reporting. This amp gauge is the Clark Kent of gauges.