1000 miles in a day requires riding steady, but does not require speeding. I-10 is used all the time for people riding coast to coast (in 50 hours). It is fast and easy. Try to time your trip through El Paso to avoid rush hour, though I have hit a wall of traffic at 1:00 before. Good tips on the Iron Butt website.
With a smaller gas tank I would certainly try to plan for gas stops ahead of time, based on the mileage you are comfortable getting out of a tank running 80-85. The website www.thenextexit.com
is a good resource for planning gas stops on interstates.
I wear a flip up helmet, and am a white guy. At checkpoints I always kill the music (i-Pod remote) and flip the helmet up. I am always waved through with no drama at all.
As has been said, I-10 is kind of boring. Do you ride out there for the IBA certificate (I'm assuming that's what we are doing here), and then take 2-3 days to get back to Austin sticking to smaller highways. Big Bend is nice this time of year, as is the Texas hill country. If you need a place to crash for the night in Lubbock, I'm your guy.