1969 Dart Street/Strip (Re)Build

I have heard that its best to find optimal timing for your combo FIRST. as it effects air/fuel mixtures. I know that advancing my initial timing leaned my car way out at idle. what was your air/fuel # at the top end of the track? I have my wideband set up and will be making passes friday. my car idles right now at 12.9-13.1 and at WOT up round 5000rpm im 13.9-14.1