Quick refresher on ignition wiring....

[essenz]

I am doing a little overhaul on my 1966 ignition. I have the after market Mallory Unilite (#501), and a 1-wire alternator.

Here are my questions, and what I need help understanding.

First, I have an aftermarket wiring diagram for the 66 Lincoln. The ignition switch has 5 terminals labeled:

GRND TERM - goes to temp sensor and indicator? Is it ground?
C - Red with green strip - goes to resistance wire and COIL+ and starter relay (fireall side, "I" on most starter relay diagrams)
A - Black with green strip (goes to some indicator lights) - this terminal post in the center
S - Red with blue strip - goes to starter relay (post nearer to batter, "S" on starter relay diagram)
B - yellow wire - appears to be hard line to Battery Postive

Here's my questions. First, I have some new accessories that call for "keyed" 12v power (some new aftermarket gauges and an electric radiator fan controller), which of the ignition switch terminals is "keyed" 12v power? Or is there a better source somewhere else to use, like maybe off the starter relay?

Next, on the Mallor unilite install diagram, they have one wire labeled as "...goes to ignition switch..." I assume this is the "C" or red wire with blue strip, correct?

Lastly, what does C/A/S/B stand for?

I have slightly more work in my situation because my car had factory transistorized ignition - that was pulled out 15 years ago when I wired the Mallory. The wiring was recently removed again while doing some engine bay work, thats why I need to refresher...