Originally Posted by PWMDMD
I don't understand what you're trying to accomplish? The difference between a 0W-16 and 0W-20 is their viscosity at operating temperature so how would mixing two oils with the same cold temperature viscosity help your situation?
OP is in NY and unlikely to see the -40F / -40C where the two oils are the same, certainly not for very long. Above that cold (very cold!) point the 0W16 should be thinner... should be, although without actual curves it's a guess. More typical winter temp would be 10 or 20F above zero.
I'm thinking, does it matter? Car is in NY and likely to rust away before giving mechanical problems... just use 0W20 and find something else to worry about (like parking tickets, snow tires, taxes, ...).