Much as "Slow Food" is a contemporary rubric for "what was once normal," so too was all bread once made without commercial yeast, where nowadays, making something "sourdough" is presented as a kind of achievement. Ciabatta is a bread originally made by poor people, likely first in Liguria. I learned about it just south of there in northern Tuscany, where they pronounce it "shabbatta." It means slipper.
The Tuscans have a well earned reputation for being cheap. Their nickname is "mangia fagioli," bean eaters. Before the "discovery" of Tuscany by the British and then everyone else, the undisturbed culture was austere and magnificent at the same time. To save money and resources, Tuscans baked bread without salt (you get used to it) and used more water in order to use less flour. They needed something cheap they could fill up on, like beans. The concept of artisanal sourdough ciabatta with competition quality voids separated by filaments of gluten would be unrecognizable to an old school Tuscan, and preposterous if explained. Among many things, they would want to know how it would hold the oil.
I don't bake to live, the way the Tuscans did. Baking for me is a leisure activity allowed to me by a wealthy society, a fun "project." When I do this, I try to remember people I've known who were connected to the old way. Somehow, this gives the outcome more meaning than just saying, "Hey, look at these holes." If there is a purpose to my baking beyond fun and food, it is this learning experience.
Being a right brain guy, all I can tell you is that this was about 85% hydration, with long cold hydration for the flour and fermentation for the bulk dough. No question, in all the time I've been reading this site, Pat's comment, "Get the fermentation right." is the most useful and important thing I've learned. Oh, and if you're using that new baking steel idea, try lowering the rack and putting the steam above, otherwise you'll have a pretty tough bottom crust.