That’s great that you’re making progress! I’m amazed you could ferment a dough at room temp for two days. Anything beyond 14 hrs (and that’s with winter house temps below 65), I’d have slack soup instead of dough. But amount of starter factors in. I’m using 75-80 grams of starter on doughs with approx 500 g flour. If you’re using much less starter, perhaps longer works.
I get medium holes if I use whole grain, and big holes with white flour and lots of water. Are you referring to large holes in bread on the blog about starter maintenance? That’s not my blog/bread – I’m sorry if I misled you on that!