My suggestion would be to continue with the high mileage oils.
I love my Maxlife, Quaker State High Mileage, Defy, and Mobil 1 High Mileage oils. Sure they don't have a starburst, sure they are a few more dollars per 5qt jug.
But they do a good job keeping things from leaking and have a more robust additive package.
I can get really good deals on 12 quart boxes of oil at Costco. If you want to go conventional you could do what I do in my Taurus and mix 2 quarts 15w40 with 3 quarts 5w30 and make a much thicker additive oil. It really slows down a leak that I don't want to pull apart the engine to fix on my Taurus.
And BTW, once I am out of my current stash I'm planning on going to a 10w40 High Mileage in my Taurus. Although now that I think of it that might be a few years from now.