The night before you plan to make the cinnamon rolls, you'll need to prepare the dough.
Spray a large glass bowl with nonstick spray. In the bowl, combine the 1/2 cup fed sourdough starter, 4 cups of flour, 1 cup of water, 1/2 cup melted butter, and 1/2 cup sugar.
Mix well and cover with a clean kitchen towel. Wrap a rubber band around it to seal it so it's tight. Allow it to rest in a warm place overnight (8 hours) or no longer than 24 hours.
When you're ready to make the rolls: Preheat the oven to 375 degrees.
When you are ready to begin, remove the cover from the dough and add the 2 eggs, 1 tsp baking soda, 1 tsp baking powder, and the 1/2 tsp salt. Mix it all well with clean hands. It's really the best way to make sure the eggs mix in well.
Place more flour on the counter and roll the dough out on it. You may need to add more flour or nonstick spray as you go but be careful not to add too much flour or you'll dry them out.
Roll your dough to about 1/2 inch thickness and work it into a clean rectangle shape. You may need to trim edges to get a rectangle. Odd shapes don't roll as well.