First, your 1965 won't have the "melted bulkhead connector" concern since it feeds the large ALT and BAT wires thru dedicated buss-bars, not the spade terminals, at least true in A & C bodies (and only 1963 & 65). But, your MAD Bypass still keeps the large charging current out of the cabin since corroded ammeter terminals can melt.
A "65A Denso alternator" is hardly defining, thus no answers. If "3 wire" means 2 field wires and the large output stud, then it sounds like a Mopar type (at least thru my 1996 2.4L and 1980-90's trucks). Those are wired the same as the 1970's square-back alternators, so read those many posts. You can use your 1965 Vreg with it if you ground one field terminal, or get a 1970's Vreg. In the 1990's, they moved the Vreg circuit into the PCM. When that fails, smart Dodge truck guys have just intercepted the wires and rigged an external Vreg, to avoid buying an expensive PCM.
To bypass the ballast resistor, I have used a single male-male spade connector, to not molest the factory wires. If you can't find one in the bubble packs, make a short jumper wire (12 awg) w/ 2 male spades.