Sounds like you are talking about recon planes and engines. Many oil choices and many engine choices too. DA, 3W, BME, conversions or whatever. Not that long ago there were no synthetic oils to speak of and these things have been running for many more years than the 45 I am old. Like everything there are opinions we all have, good or bad, right or wrong. Make a choice and go with it being the bottom line. Nobody in this hobby has the time or money to test like that, us nor the manufacturers. Only the G Man could underwrite studies like that. We have a few guys here that run the cheapest oil they can get at Wally World or the Dollar Store and they have no issues. Not that I am advocating cheap oil but another example of what works.