Any difference between two 20-grade oils is going to be inconsequential. The only way to get something meaningful is to increase the grade no matter what brand, what winter rating, what Noack (not NOAK), or what pour point.
One can scratch along the edges all day long but do you really want to help mitigate dilution or not?
One can scratch along the edges all day long but do you really want to help mitigate dilution or not?