I'm glad that some of my experience with the MAF Table helped you to have a more stable fueling
Like I said it wouldn't give you power but just likely to stabilize the AFR curve.
as for the timing getting pull after a few run ,
you said you had 29 BTDC and going down to 24 after a few pull.
you are running stock timing map with probably a richer AFR ?
What come up in my head would be maybe
1= water temp ?
2=oil temp ?
3= quality of gas used ? (different brand aren't the same as we know it)
4= lean spot a little bit before your peak power ? which should be around 6850 rpm (stock)
having a good oil cooler help keeping temp down with those engine !
it is definitely helping !