From what you just explained to me about your oven temperatures it sounds to be about 572 degrees F in our conversion from Celsius to Fahrenheit. I am not good at figuring that out, but from what I can see on conversion temperatures from the web, that oven temperature should have been good in baking your pizzas.
I am not experienced in using flour with your protein content. My flour I use is a high-gluten flour and has a protein content of around 14.2 %. That is another reason maybe your pizza didnít get as much of coloration in the crust, in my opinion. I donít know anything about flours from Germany or if your flours have other added ingredients or not.. It is interesting to hear about other countries and what they have available in terms of flour. Maybe you could try to use the flour you have access to that is 11.2 %. At least that would get the protein up some.
From what you explained to me in you past post, I would tend to believe you dough overfermented. Since you said you water wasnít that warm that you used in the final dough, I am not to sure about that. Do you mix by hand or have a mixer? If you knead the dough by hand or even have a mixer, if you knead the dough too long, your hand temperatures can even up the final dough temperature. If mixing by a mixer a long mix time can also help the final dough temperature to become to high. Maybe you could try a cooler water temperature for the final dough mix.
Your oven spring could also be related to different things. It could be your flour or how you open the dough. In my experience, when you open the dough balls, try to keep an edge or rim and not try to press much on that. Just gently press you fingers around the middle and then try to slide you pie around in circles, while pressing on the middle. When you made your regular Lehmann dough were there problems with oven spring? If not, then I would tend to believe some of your problems were related to you dough overfermenting.
If you have a chance and want to try this dough again, if you could post some pictures of what your dough balls look like, maybe I could help you more.
Let me know if you need any other ideas. I am not an expert on any of this.