We don't know your income, but I'm going to assume you make less than 180,000, in which case the most obvious way to maximize pre-tax savings would be to max-out your 401k, which would mean contributing $18,000.
I'm no expert about college savings, but I did learn that though 529s ARE state specific, you actually can sign up for them in any state you want and most of them can be used in any state you'd like. I live in WA so since we don't have a state tax, there's NO advantage to me using our state plans. For you, there may be some particular advantage to using a TX plan. You'd have to look into your particular options in TX, but I think there's a good chance that you could sign up for Texas 529 and use it in another state. You'll have to research it to find out if this is true though!