It's funny how we all read the same words to mean different things! I read that the question is whether we can, at this water level, navigate between the point separating Gunsight and Padre Bay and the two small islands clearly shown in the google earth photo, which would have been about 30' deep last November.
I think it is still usable, but not 100% positive. It was usable on January 1 with plenty of water to spare. Lake level is down about 18' since Nov 1, 2018, so using your own depth, still should be 12' deep.