I’m glad the final product worked out well. Since you speak of shaping the muffins, I’m assuming you were doing the oven version – just to confirm because the skillet version hydration is certainly unmanageable for anything but scooping with a large spoon or measuring cup.
Assuming you’re referring to the oven version where you shape the patties, I’m guessing either your flour absorbed less water than mine, or you took the bulk fermentation much further than I did. Interestingly, your experience is in sync with the Cultures for Health recipe I worked off of. It had more flour for the same amount of liquid AND had scooping the batter. At those ratios, I had a quite dry dough that could never have been scooped, but it sounds like you might have been fine. (I tend to have a wetter, not dryer, starter than most, so that wasn’t the issue.)
As for using the fridge - always a good resource! I didn’t bulk in the fridge, but once shaped, I proofed in the fridge to buy myself time.
I guess next time try less liquid and/or a shorter bulk fermentation. I’d love to hear how it goes! For reference, when mixing the dough of the oven version, it was sticky and messy – not low enough hydration for kneading on the counter traditional style.