Having pulled my hair out on this one this might help you. I agree you really need to go to wideband O2 to be accurate. After that, minimum burn time is a mixture around 12.5-13.0, which is why you get max power at this AFR. Above or below that burns slower, regardless of AFR. When you are outside the fast burn AFR's and you think you can run more timing and it detonates, most people add more fuel which is not the problem (still burns slower but cools the mixture). Max cylinder pressure is happening too quickly due to too much timing (talk about damage...). Adding boost speeds up the burn also so the game you must play is this. Dial in the AFR you wish (which is why you need the wideband) and then find max timing (for most burn time) that you can get away with per load. The sweet spot I have found to be around 23 degrees for 12 lbs. at approx. 12.6-12.8 AFR. This makes a huge amount of power. Then, take more timing out under more load and add back in for more RPM's.
89 TTA #162, 38K miles. Built motor (3k miles), frame connectors, 70mm TB, twin pumps, 3" DP with Aero-turbine, massive intercooler, 3.42 rear, non-lock art carr tc, FAST B2B wide band O2, 75 lb. injectors, T67, RJC power plate... **RIPNAIR PROJECT - 10 second car that gets 30 MPG on the road**