You sure make your wiring complicated

My setup is Battery positive to cutoff switch, other side of cutoff switch to starter terminal stud with a jumper wire from the staerer terminal stud to the starter relay to where the battery power is normmaly connected.

Obviously throwing the switch will not kill the engine, so my one wire solution was wiring an ignition kill circuit that goes from the ignition to ground through a normally closed microswitch mounted to the battery cutoff switch.

I'm not sure this is 100% NHRA approved, but it has passed tech for years.