OK, my first total failure in the artisan area, but I'll probably try this again anyway.
Dough consisted of poolish with 100% hydration (that's 100% of total hydration), a little bit of flour added at the dough stage with a tiny bit of yeast and "regulation" salt.
Target was 150g of flour at 80% hydration. Think, "baked poolish" - almost. Tried doing it in a cloche - first time there as well. Too many variable changed to succeed.
But I think that if I reduce total hydration to about 70%, make my poolish based on all the water, this could work. Have to stiffen the dough enough to be able to let it final proof outside a proofing container. Pouring slack dough from the container directly into the cloche is guaranteed not to work.
Q for the pros: what if I do final proof in the cloche base (room temp) and just preheat the lid? This one strikes me as as much about the bake as about the dough. You dig?
Try a cold start. Don't preheat the cloche. I seldom enclose my bread for baking, but several here have experimented extensively with starting temps*. Regarding cold starts, I have been cold starting the oven for my panned sandwich loaves now for a while. I get a more even oven spring and fewer blowouts.
A ceramic cloche or cast iron Dutch oven' temp latency may affect the timing, but that's trivial.
cheers,
gary
* Ha, I found one: http://www.thefreshloaf.com/node/20715/baking-bread-cast-iron-no-preheat-method