Questions on wiring Ignition/ supplying power to the fuse box

What we need at this point is a link to the manual with your wiring kit Some of that should be documented in that manual.

To "demistify" (I hope) the ignition switch, here is what you have going into and out of

MAIN POWER IN This originally came off the "welded splice" and was NOT fused.
"IGN1" ignition run.......this powers the cluster, warning lamps, ignition system, VR and alternator field, and smog devices and electric choke if used

"IGN2" This powers ignition system ONLY in "start" because IGN1 goes dead in "start."

ACC This feeds out to the ACC fuse buss in the fuse panel and feeds radio, heater, wipers, etc It is of course "hot" both in "run" and ACC

START....This is normally yellow an goes to one of the coil terminals on the start relay.