Timing set - Just making sure

Well I adjusted the ignition timing this afternoon. I loosened the hold-down bolt before checking to see what the timing was set at previously, so I rotated the distributor before I realized what I was doing. Anyway, I put the timing at what I think is 14º BTC from the #1 spark wire, correct? The illustration shows what I put it at from memory, let me know if it's right. What is ATC and the 12 there for, btw?



Edit: This is on the skinny portion of the balancer, by the way, and withOUT the spout connector in.

Also, if you can, explain to me what pinging sounds like and when I should expect it. I'm running 90oct gas right now and I don't hear anything unusual, but then again...I don't know what to expect. Let me know.