These engineers made an engine so good that a Kia crossover ate 9 of them up, 1 every ~66k miles.Not a thing about thick or thin. My rule is the engineers have some inside info on what is best. So viscosity and OCI go hand in hand with your OM. But taking advice from even the best minds at BITOG go a far second place from the OM.
https://bobistheoilguy.com/forums/threads/600k-kia-went-through-9-engines.354944/
MOFT>CAFE, plus great additives that help an oil pass Porsche A40 test. That's the recipe for a long lasting engine.