I agree with John that you may have a problem getting the dough to hold out for six days of cold fermentation.
First, your dough formulation has most of the earmarks of a classic NY style dough formulation--going back to the early days of the evolution of the NY style but using dry yeast instead of fresh yeast and a cold fermentation rather than one at room temperature.
Second, at 65% hydration, that is about 5% higher than the rated absorption of the BforB flour. However, your dough preparation methods appear to have overcome the stickiness problem that often accompanies using a hydration value significantly in excess of its rated absorption value. But, the higher hydration value will usually translate into a faster fermentation that can foreshorten the window of usability of the dough.
Third, you did not technically subject the dough to a classic autolyse because all of the ingredients, and especially the yeast and the salt, were all combined together. Moreover, I calculated that it took you about 63 minutes to make the dough, and perhaps a bit more when you add in the brief periods of time between the different steps. During the time that the yeast is in the dough, but before being refrigerated, the dough will start to ferment and, in your case, will continue to ferment for the 63 minute duration mentioned above. That fermentation will further shorten the window of usability of the dough. In short, unless you have an exceptionally cold refrigerator, you may not get out to six days. I think I would shoot for three days, or possibly four if after three days the dough is still firm to the touch and there is not exceptional bubbling formed in the dough at the sides and bottom of the storage container.
Please let us know how things turn out.