Nevermind.
The back straight at COTA runs about 262° True.
At 5pm tomorrow in Austin, the azimuth to the sun will be about 242° and it will be about 23° above the horizon. That's slightly less (for the average man) than the width of the Hawaiian "Shaka brah" sign (AKA, "hang loose, mongoose")* held at arm's length.
At 6pm it will be at 252° and 11° above the horizon. That's a skosh more than the width of your clinched fist at arm's length.
I foresee complications brewing.
* Not to be confused with 'Hook 'em Horns.'
Nevermind.