I think you need to go a little farther out to find Snapper.
Sabine Bank is pretty close in and pretty shallow.
When I fished Snapper, they were closer in during the Spring and Fall.
In the Summer, we didn't do too well in shallower waters.
If I were you, I would try to hit at least 50 ft. of water or more.
http://www.charts.noaa.gov/OnLineViewer/11332.shtml