What are you're fuel trims at at WOT? They should be at zero. Like suggested you want the hottest spark that you can get without having any kr.
The WOT section on the timing table on your car should be in this range.
If you had HPT you could do one of these.Wich would be a timing tune.
I could run about 22 degrees with no kr on 87....and 25 on 93...what are you using?