I'm not sure that you should try to extend the fermentation window further. The purpose of using the poolish preferment in the first place is to speed up things so that the dough can be used within a short period of time, about eight hours with JerryMac's dough recipe. As it is, your combination of room temperature prefermentation of the poolish (4 1/2-5 hours) and the two days of cold fermentation is perhaps equivalent to over five or six days of cold fermentation, and possibly even more. If you push the window out further, by going to three days of cold fermentation rather than two days, you run the risk of running out of residual sugars to contribute to final crust coloration. In fact, I think you are already low on residual sugars due to the way that the poolish, with a lot of yeast, gobbles up the simple sugars in the dough as soon as they are available.
I believe it is possible to make a cold fermented dough using a poolish but I think it would be necessary to reconstruct JerryMac's recipe to do that. You could perhaps add some diastatic malt as part of the final mix, but I have tried that in a preferment based dough and it did not help all that much. I think the recipe has to be reconstructed. Off the top of my head, I am thinking that you will have to use a more traditional poolish method with a very small amount of yeast in relation to the poolish flour weight and a long (several hours) room temperature prefermentation before proceeding to the final mix. Even then, I might consider using some diastatic malt.
You might try the longer cold fermentation if only to teach you some of the principles involved in using preferments in conjunction with cold fermentation of the dough. If you do proceed along those lines, I hope you will post photos of your results.