ZDDP content of commonly-used oils: https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1387987/1.html

The quest for "best oil" is as fallacious as the quest for the "most beautiful woman". No such thing, although Monica Bellucci comes close.

As far as zinc goes, it is possible to have too much zinc. And while zinc is the first word in the chemical name of the compound most commonly used as an antiwear additive, I believe it is actually the phosphorus in the compound that does the work. Here's an excerpt from a paper on the use of zinc dialkyl dithiophosphate (ZDDP): "ZDDP decomposes to form a polyphosphate film on the surface".

There are many good oils specifically blended for use in high performance flat tappet engines. If I had to pick a family I'd go straight to Joe Gibbs Driven oils.

R.