I hear you on vehicle regrets; it happens. In some ways I wonder about flipping vehicles more often, in order to prevent that (ignoring the financial aspect for a moment--taking that into account, that is why I don't). I can't see what would be wrong with 0W20, it's what is spec'd and at your low miles/year I can't see a problem. Myself, I'd probably go thicker just because I could and because my habits are much different (lots of highway). I was going to recommend buying filters in bulk so as to get a price discount, but if you are doing one change per year then I'd probably just buy anything on an as-needed basis. No real reason to stock up.