Mixing oil weights

All modern engines are machined and parts are designed for low friction/tight tolerances. 5w/20 is the factory recommended oil type for MDS equipped Gen III. The engine manufacturers have spent years on design and millions of miles testing to establish proper lubrication specs for long mileage and warranty periods.
Don't think you are smarter than they are.
The Gen III engine tick has been there for many years and millions of engines. Not a biggy.
Use what the manufacturers have recommended unless you have rebuilt the engine in which case you will have to rely on the engine /parts makers recommendations.
Current factory engine machining equipment is much more refined and precise than almost any engine rebuilders have.