I think I have tried just about every type of preferment for pizza dough and if I were forced to pick just one for cold fermentation applications such as you have been experimenting with, I think I would pick a poolish. It works the fastest (because of its higher hydration than other preferments) and it is easier to spot the break point. The poolish also produces good amounts of acid without overly impacting the extensibility of the dough. If I were to make an entirely room-temperature fermented dough, then it is quite likely that I would go with a stiffer starter/preferment along the lines discussed by Marco and other members.
As you become more proficient in the use of natural starters/preferments and feel that you understand the basic principles of their use, you might consider other forms and protocols. It is hard to know which ones to pick and how to devise an appropriate fermentation protocol because they would have to be usable within the constraints imposed by the rules you have to follow at market. Also, I think that there would have to be a significant advantage in using them over what you have been using most recently. Unfortunately, you will always be having to contend with temperature variations over the course of the year and devising methods to allow you to make functioning dough balls despite those variations.
Where do you think you will go next?
I plan to go back to the posts in this thread since you have been posting pH values to see if anything jumps out at me in the way of patterns that might be helpful to detect and use pro-actively in making your naturally leavened Lehmann doughs. If I see anything, I will let you know.