Starter growth - Upscaling limits?
I maintain about 3/4 cup by volume of starter in my fridge. Some recipes I've been looking at are asking for 1 cup of starter. So, my question, by way of example, is that I presume I could take about 1/2 cup of the starter add 1 cup flour (~113g) and 1/2 cup water (~113g), let ferment overnight and then use 1 cup of the newly fermented starter in my baking.
At some point in time it seems to me that, depending on the recipe, one could add so much flour/water that it would take longer than overnight for the population to grow to give a strong/viable enough starter. For example, and this is just to articulate the problem, not a real world example, but if one added 5 cups of flour and appropriate water to 1/2 cup starter, it seems that it would take a considerably long time for a viable starter, and it might even not work.
So, is there a rule of thumb regarding how to upscale starter? For example, I could see a rule that says, for every gram of starter, the maximum you would want to feed it is 4x. So, for 40g of starter you might not want to go over 120g flour (and appropriate water).
I apologize in advance for the wordiness, but I couldn't figure out how to articulate this concisely!