Sperlonga recipe without high gluten flour
I work at a bakery in a grocery store as a scratch baker. The lead baker has been baking for 40 years, and 6 months ago we had a change made to our sperlonga recipe. We were no longer allowed to use Sir Lancelot flour (14.2% gluten) and have to use King Arthur flour (11.4% gluten). He has been working to get the consistency of the previous bread by experimenting with adding or subtracting water, increasing or decreasing poolisch, and changing the temperature of the water. We use 90-F water, mixing a 90lb batch for 4m slow 10 high, and tried 60-F water as well.
Due to recipe and ingredient labels, we are restricted to the King Arthur Flour, salt, malt flour, and yeast. We make and use poolisch as well. Does anybody have any ideas that I may suggest to help give the sperlonga its high gluten flour texture while only using 11.4% gluten flour?