Made another attempt at the MB sourdough and I made some progress. It was obvious from previous attempts that it was underproofed. I realized that I'd been bulk fermenting the dough at far too low of a temp (70 F). I use that temp for bulking baguettes, so I thought I was supposed to use the same temp for levain dough. But I re-read the bulk fermentation section, and saw that it recommends a bulk fermenting temp of 80 F. Doh! Would it be too much to ask the authors of MB to have listed the recommended bulk fermentation temperatures on the master recipe page? I bulk fermented the dough at 80 F for 3 hr 30 m with a total of 4 folds. The dough was quite elastic after that. I'm still hesitant with scoring and my shapes are still not symmetrical but i'm happy. I'm not going to try and make sourdough and baguettes again until I become a lot more organized. I was all over the place. My baguettes really suffered from it although I'm happy with the crumb.