In my opinion, it was marginal still for those days standards. But is just my opinion. If you are driving around the country, you will barely keep the car at idle so the charging deficit will be marginal, but on big cities will be mostly at idle between traffic lights, loosing load from batt being discharged constantly. I guess back in the days with less heavy traffic conditions we can say that could be considered as a “standard” stage? Dunno

Yes, you are 95% correct on the interpretation of my words. As many of you know, english is not my mother language so sometimes it CAN be hard to my explain what I’m trying to say.

About the wire between alt and batt, that will VIRTUALLY bypass the amm but, also provides an extra path for the load coming/going through all the network. If some problem is present on wiring you are not fixing but hiding it.

Alternator output has been always a problem anyway, from factory.

With a damaged charging system ( damaged alt, belt or alt wire ) sure you should keep the load demand as low as posible because:
-Ignition system will need the best load and voltage rate capacity as posible.
-Ammeter will be safer, same as all the wiring between Batt and main splice.

The OP can be confronting several issues at the same time, but yes, still with an inoperative alt ( for WHATEVER reason ) the batt should supply the power to still keep running the engine. So it could be a problem between batt and main splice ( ammeter included ) down the under dash harness tape which spreads the power to everywhere.

And is not about voltage really, since voltage can still run through a hair, but amperage, which needs to get a good path to supply the requested power. Of course, a damaged path causing resistance will affect both, voltage and amperage, and both are always in a straight relationship, but a good amount of amperage being supplied, will affect less the voltage rate.

Energy is based on watts… increasing voltage or amperage on a steady resistance. Electric devices sucks amperage to provide watts based on a steady voltage rate and resistance.

Increasing voltage will require less amperes to produce watts.

Amperes are sucked in by the devices not pushed in by the source, to keep their energy/work capacity,

Resistance will produce amperes restriction and poor work capacity.

Etc…