Ideal amount of oil for a /6

Why would you use synthetic on the break in?
Rug I dont have any problems with ring seal. And I really think a lot of wear comes from start-up. I think we shuold put the best oil in for the worst case. Because it soo slick I just believe the sythetic is the best oil for the job. Ive done a few cam changes on my engines and there were no wear marks at all.
I picked the tip up from another BB drag racer about 10 years ago. Started doing it in my tractors and smaller engines. And here I am.
Frank