Well, I went diggin' and found a couple of things. Firstly, I had a few details wrong in the schematic I interpreted from the directions in the manual, so here is the corrected version:
Then I learned that positive feed to every electrical component except the starter on a car equipped with an ammeter must go through the ammeter and then on to ignition to coil, fusebox, etc.
I decided to run a jumper wire from the downstream end of the fusible link in wire #27 off the starter right to the "BATT" terminal on the alternator. Well hello there - everything (except the bypassed ammeter) worked like a charm. The car fired right up and actually seemed to run a bit smoother than before along with a startlingly crisp response when I blipped the throttle. First conclusion is that the fault exists somewhere between wire #27 and the ammeter since there was no power to ignition or fusebox prior to the jumper. Secondly, this exercise appears to have exposed a weakness in the system somewhere between the fusible link ,ammeter and the alternator because of the very noticable improvement in idle quality and throttle response after the bypass. I also noticed a possible ground issue in my cooling fan circuit as the fans ran intermittently when everything else was working perfectly. Back to the garage to start tearing into that portion of the harness to see the condition of wire #27 and check the ammeter then wires #39, 41 and 25. I'm sure I'll find the problem somewhere in that group. I'll keep updating...Thanks again for all the help.