0w-16

With some oils getting into the 0w8- and 0w-16 ranges, doesn't this leave very little protection cushion if the oils suffer viscosity loss due to something like fuel in the oil? Could this reduced cushion of protection be made up by additives?

I've been researching for a few months on all the different 0W-16s on the market. I've ran Pennzoil, Valvoline, M1, and Toyota OEM. Very subjective, but the M1 seemed louder than the rest. Toyota OEM is very high in moly according to VOA others have posted. What are you running, why?