Best Alternator to give sufficient juice to the MSD 6AL ?

All of those are recipies for more problems.
As already stated, the MSD 6 series pulls 1 amp per 1000 rpm.
So at idle its pulling no more than a points or even a Chrysler ECU.
The coil on an MSD is fed from the MSD's capacitor so that's a red herring.

On the other hand, these new replacements, especially those based on the revised squareback, draw far more field current than any standard factory alternator through 1976.
Go look in your shop manuals at what the field current draw should be, and then compare it to what you're buying.
If its pulling more amps than the MSD will pull, then its a zero sum improvement.
Worse. The voltage regulator may not handle it well.