I am assuming this adapter does the same job that all the diy jumper wires do in this website,
https://woodworkerb.com/home/datsun-240z-rebuild/datsun-240z-alternator-upgrade/
I also read that if you have a voltmeter not an amp meter then you do not need the diode, so unless someone proves this false i will try this configuration tonight without the diode and let you know how it goes.
thank you