The photos below show a couple of my recent attempts at French baguettes. This was after the passage of several years, so I expected to be quite rusty.
The first baguette was based on your original recipe but reduced to produce a single baguette of around 11 ounces (dough weight). I also used the KA French-style flour (at around 11.5% protein) and a natural preferment (my own) at around 30%. I used no commercial yeast. I estimate that the hydration was around 54%. The dough for this baguette was prepared in accordance with your instructions and went into the refrigerator about an hour after kneading (by hand), where it stayed for around 3 days before shaping it and letting it proof for about 3-4 hours in preparation for baking. The baguette was baked on a pizza stone that had been preheated for about an hour at around 500 degrees F. To get some steam onto the baguette to create a nice crust, I had placed a metal tray filled with clean stones onto the lowest oven rack, just below and to the side of the pizza stone, to be preheated at the same time as the stone. When the dough went into the oven, I poured a bottle of water onto the heated stones, and I also spritzed the sides of the oven with water from a spray bottle. After about 5 minutes, I lowered the oven temperature to around 450 degrees F. I don't know whether all of this this was good technique, but the finished baguette had a very nice mild tangy flavor and a fairly open crumb.
The second baguette was similar to the first except that it had a dough weight of closer to a pound. I also used an autolyse, along the lines of the Calvel autolyse. The dough also went into the refrigerator but only after a room-temperature rise of about 10 hours. This was not intentional. I simply forgot the dough on my countertop. The baguette remained in the refrigerator for about 2 days and was baked about 4 hours after shaping and proofing at room temperature. This baguette also had a nice sourdough flavor but the crumb was tighter than the first baguette.
I found the toughest part to be the shaping of the dough into the baguette shape without the seams opening during baking. I tried the envelope method of shaping and also the end-to-end method recommended by KA. The second hardest part was getting the shaped baguettes into the oven. For the first baguette, I placed the dough into the fold of a piece of lightly-floured canvas that I had draped in one of the trays of a metal baguette baking pan and folded over to cover the dough so that it wouldn't dry out while proofing. It wasn't as fancy a scheme as yours, but it seemed to work reasonably well. When I was ready to make the baguette, I rolled the dough onto a dusted wooden peel and, after scoring the dough with a lame, slid the dough into the oven. I managed but it was not a particularly masterful job. The peel wanted to go one way and the dough another.
The dough for the second baguette was shaped on my cutting board, and placed for proofing on a sheet of parchment paper on my wooden peel. After scoring the proofed dough with the lame, I slid the dough on the parchment paper into the oven. I found this to be an easier approach than the one used for the first baguette.
After seeing the photos, I am sure that you will be able to offer some suggestions for improving my performance with the baguettes. What I was hoping for was a more open crumb and an outward appearance like yours. I have a cloche that I bought from KA and wondered whether that would be a good choice as a mechanism for baking the baguettes. The cloche, with the shaped and proofed dough in it, is placed in the oven cold--not in a preheated oven. The cloche would seem to involve less handling of the dough.
Any tips you can offer will be much appreciated.