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I always find it best to read and make as much of an educated GUESS as we can, armed with the best information at hand.
Oh! Is that why your linked information is largely from the pushers of engine oil additives, and internet hot rod bulletin boards where the BS flows like the Red River in early Spring? Just askin'!
For those who wish to make their own choices about what constitutes "best information", keep in mind that the certification tests for the current oil service ratings (recently SM, now SN) include two different flat-tappet engines, and there's less alarmist, less commercially-biased, and more realistic discussion and primary-source links here and here (though it's festooned with unsupported-opinion comments, it contains a good deal of primary-source info from those in a position to know WTF they're saying), and here. An interesting tidbit (one of many) from that latter link: The addition of ZDDP usually results in reduced cleanliness, higher engine temperatures and more deposits. Some studies have shown that going past 1400 ppm of phosphorus will increase wear over the long term, and going above 2000 ppm will begin to break down iron and result in camshaft spalling(…), so if you are bound 'n' determined to add stuff to your engine oil because you think you are a better petrochemist, tribologist, and metallurgist in your driveway than the ones the oil companies pay very big dollars to put their very specialised educations to practical work in very well equipped laboratories, or because you gotta-just-gotta spend unnecessary money, or because Jaybob down at the racetrack said you should and you believe him on account of he's built three motors that haven't blowed up yet or for whatever reason, then at least do the necessary math and don't use too much, which is what you're doing by dumping in an entire bottle of whichever miracle mouse milk you're adding to your oil. See here.
(Also: reading more stuff does not necessarily make someone more informed. Specifically, if the stuff being read is not factually sound, reading it and believing it makes one less informed, more misinformed, and/or more confused. Facts and science trump opinions and beliefs and guesses and preferences…every single time.)