what ever anyone thinks, you can't properly set the timing via vacuum nor by feel. Proper instrumentation is your best friend. Besides, why would you not want to use a timing light...basic timing lights are cheap!
I set my '81 454 at 4 degrees advance for smog testing. I haven't changed it and there was no audible pinging on my last 1000 mile trip mostly over mountain between California and Oregon with many 6% grades lasting 8 to 10 miles each.
I would like to do some experimenting with the advance curve and jetting on the Quadra-crap, but I certainly wouldn't do this with out using a timing light. Now, my other issue is that I can't find any information nor anyone that knows how for a non-race car 454...sad!