for a 1969 Dodge Dart the wiring diagram shows the "G" terminal of the starter relay going to the neutral safety switch. Where does this wire go for a manual transmission? Later years used a clutch safety switch so the wire goes there in 1970+ (i think). I know the wire is grounded, but specifically where did it connect to?

clutch pedal switch, no other place.

I know some earliers assembly never got a safety switch anywhere ( dunno what year was the last ) and in fact this relays got a tab welded to relay housing to get a chassis ground, but if you have the prong, will go to the clutch pedal switch

1969 and earlier relays for manual trans car were soldered to the side of the relay case
As in S101 and S78 in this picture