Good Method to Add Wiring For Add-Ons

That is where I THOUGHT was OEM(for our 67), but wasnt. Chasing my tail for a while until I realized it was from Motors Manual. I since found the factory 67 supplement for our 67 cuda from @Mattax Seeing how it was 1st year for 2nd gen cuda, Ma Mopar "forgot" to put barracuda specific schematics in the FSM. Sorry not trying to confuse/ derail, just want you to be aware of possible differences in schematics.
All I know is that diagram is from mymopar.com.