Okay, I was trying to gauge whether your goal was realistic, and it seems like it might be. I got 513 on the NextStep half length about 2 months out and ended up with a 522 on the real thing. You'll need to take official samples to get the best sense, and NextStep isn't as bad as Kaplan or TPR but it's certainly deflated.
Are you going to count as a TX resident for the purpose of TMDSAS?