Dang. It worked...

I used an old bread pan instead of a banneton, and shaped the bread before putting it let the dough in the pan in a tea towel rubbed with rice flour overnight in the fridge instead of just in a bowl in the fridge. The dough was just under the lip of the pan when I put it in, and I wrapped the whole thing with a produce bag that I closed with a twist tie.

When the oven and Dutch oven were hot (at 500) in the morning, I got the dough out, and it had risen over the lip of the pan. I dumped it out onto a piece of parchment paper a little more roughly than I wanted; but it got there, and tried to brush off some of the loose rice flour, but didn't get even most of it. The dough just barely fit onto the lid of my Dutch oven, and I got the pot over it handily.

And then I forgot to turn the temperature down to 450. I let it bake at 500 for 25 minutes and then uncovered the most glorious oven spring I've ever had. I turned it down, then, to 450 and let it go 20 minutes, and it came out as pictured.

It's about a third again as big as the loaf I was doing by shaping it last thing before baking it, kind of proving (ha ha) that letting it proof after the shaping really does help with the oven spring a LOT and then volume it picked up was all in a far more open crumb.

Below are pictures of the crumb.  

There's a lot of good variation on the hole sizes, and lots and lots of them, and the texture of the bread itself was wonderful and far more like the artisan loaves from around here.  Someone on my Facebook page said to autolyze while waiting on the starter, and I may try that next time in addition to the shaped fridge fermentation time.

So many more experiments. I even have a "lab notebook" on all my sourdough experiments, all kept in a Field Notes notebook with all the timings and all the by-gram measurements of ingredients when I do my loaves. We'll see how it goes.

Yes. I am obsessed.