If the supplemental electric pump is only run when the engine is running, then the factory scheme is actually very good.
Power the supplemental pump direct from the alternator with a relay that turns on with key in run. Use a fuse in the line
or if the draw is low enough, its possible to add a fuse to the fuse box. Its just a pain.

Headlights if used, also benefit from direct from alternator through a relay.
There's a lot of connections for the electricity to get to the headlights - and on a-bodies especially, the wires are small.

Depending on the condition of your firewall connector, for your needs a parallel wire to the ammeter's stud might be enough. Use a well insulated ring terminal.
If the bulkhead connectors are poor, then remove the alternator feed wire from the bulkhead inside and tie in a new 8 or 10 gage wire through a grommet in the firewall.
If the battery feed connection is also poor, then 10 gage with 16 gage fusible link on engine side, then 10 gage through a grommet to the ammeter red terminal.

I thought '63 had the better bulkhead connector, but maybe that was just '65.

This is a parallel alternator feed through a grommet.
At minimum it means any current for recharging the battery will have a dedicated route from alternator.

Illustration showing battery charging

Doing it as above means only one fusible link is needed.
It also lets you monitor the battery charging and discharging.

Connecting the Alternator output direct to the battery or tying in at the starter relay does the same thing.
It gives the sometimes high charging current a seperate route to the battery, reducing the load on the main feed wire and connections.
Difference is that a fusible link is needed in the connecting line to protect against battery grounding, and the ammeter will no longer show charging.

That is why I put a volt meter in my race car to make sure the alternator is working
Easy peasy to do also
I connected it to the ignition feed, shows battery voltage before starting and alternator charging voltage when running

Some places encourage removing the alternator's feed to the main splice.
This creates a longer path through two fusible links with more connections for everything but battery recharging.
Not recommended unless running battery most of the time.

When I went EFI on my Fury, the main criteria for rewire were:

Remove the battery charging circuit from the cabin (e.g. amp bypass, bulkhead bypass)
consolidate new power needs (efi, fuel pump, stereo, etc) on a bus and draw voltage 'sensing' from that bus

so I
bypassed amp gauge
rerouted alt output to the big post on the starter relay
efi, fuel pump, stereo draw power from the big post
allowed OEM wiring to still feed the cabin - in this case I created 2 parallel paths for power to flow from the source (alt or batt) into the cabin vs the OEM in and out
I actually didn't bypass the bulkhead, I repaired it and since I removed all draw from that circuit except the OEM equipment in the cabin and removed the battery charging from that circuit, there's no issue

I used a 1 wire alt, if not I would have run the sensing wire to the big post as well.

Bypassing the problematic, old, original ammeter and using a voltmeter to monitor the electrical system is an easy decision for me, regardless how it is wired.

If you need new crimp spade connectors for your bulkhead block you can get some off Ebay. These are medium duty so they are OK for all but the 10 Gauge wires. I do not know where to get the heaver ones.
https://www.ebay.com/itm/Mopar-Male-Female-14-16-AWG-Gauge-Wiring-Harness-Terminal-Crimp-Connectors-NOS/192502001151?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649