I picked up about 1.25 volts through the system back to the battery just by using 10 guage SXL wire direct from the alternator thru the dash to the main underdash wiring harness, and another 10 guage SXL wire coming back out to the fusible link at the starter relay. Bypassed every terminal in between (think there was about 4 or so).
Headlights are much brighter at idle.
I left the ammeter wiring alone.