Tartine Troubles

I have been on a Tartine learning curve for a few weeks. I really thought I had it nailed this time. I started w strong starter (doubled in under 4 hrs) and a good levain from it. My dough temp going into bulk was in the 78-82 sweet spot and remained there the whole 3 hrs. Dough rose 30% and domed. Four S and Fs at 30 min spacing. After 3 hrs, pre-shaped, dough was pretty slack. 30 mins later final shape and into bannetons and into fridge for proofing. A boule and batard. Boule had nice oven spring in dutch oven and nice ear. But when cooled and cut in half very disappointed to find a crumb that, though light and springy, had very few larger holes. Lots of smallish holes.