I usually use self-rising flour for biscuits and self-rising cornmeal mix for cornbread. For biscuits, the reason has to do with soft, southern wheat with lower gluten for better biscuits. For cornbread....its just easier. With biscuits or cornbread, I like to add 60 to 70 grams of sourdough starter for the flavor for two cups of flour or meal.
I just posted a recipe for sourdough cornbread with cheese, onion and corn options.

Red