don’t put any cam lube on a used cam, especially on that looks that good, look at the nose of the lobes, it looks great.
A thinner oil flows faster and cools better.
I don't know why everyone is stuck on 20/50 in a hot rod engine.
What really matters in choosing an oil weight is the oil temperature. If you don’t know that it’s all a guess. That’s a quote from Lake Speed Jr. look him up if you don’t know who he is.
You say it’s not blue to the eye so it looks great to me.