Faulty battery, bad alternator, or both (photos)
I'll have to review all this to see what you did. A ground strap CERTAINLY cannot hurt. The VR must be at same voltage "at the ground point" as the battery NEG.
"How I did" mine
Look on your passenger side head at the alternator mount. Those same bolt holes are available at the REAR of the driver side head Go to the parts store and buy about a 1 ft long "starter" cable. These are "eye to eye" ends. Get a short bolt, reach back there and hook that cable to the head, bend it down to a "U" and come up and either put a sure bolt through the firewall some place or in my case I used one of the master cylinder studs.
Make SURE the VR is scraped clean as well as the firewall, and get yourself some star lock washers to mount the VR. Doesn't matter if they are internal or external