I would go with the total as well but I think the difference in your returns will be minimal over the course of about a decade whichever you pick.
I have a question on my own, are you required to have the $3000 minimum upfront to start a 529 with Vanguard? Especially if you already have a taxable Vanguard account with VTSAX (over $10,000 balance) in it.
Or can you open a 529 with a $100 and stash away $100/ paycheck? (for example)