JerryM,
Caputo Blu "Pizzeria" Tipo 00 flour only has 9% gluten so I don't see your point about high protein being best. Regular Caputo Tipo 0 (not 00) has about 12-15%, so it has more gluten than "00". Most Pizzaiola mention that 12-15% gluten is best for Pizza, hence why professional pizzaiolas somtimes use various dough conditioners for "00". Puzzles me why they don't use "tipo 0", though, which even "Molino Caputo" mentions as a very good Pizza flour on their homepage.
Anyway, I found out that I might be able to find differences in german "all-purpose" flour (Type 405) when getting it from different brands. Brands made in France and Italy will usually have 12-15% gluten whereas "405" flour from Germany, Czechoslovakia and Poland will have lower gluten content (this has to do with the actual grain used).
I also found an interesting thread in a german baking forum where someone compared various supermarket "all-purpose" flours, some specialty "breadmaking" flours and also Caputo Blu. You can barely see any difference between the resulting pizzas, to be honest. His conclusion, after baking more than 40 Pizzas, was: The flour makes little difference. It's all in the technique/preparation.
That being said I will try out some other flours when I stumble over them - AND I will check the manufacturing country on any flour I buy from now on

Oh: I found a "Tipo 00" flour in a supermarket two weeks ago. On the back of the bag it said "Type 405" in small print, so I really don't know what to say or so. I will need to remeber which brand and store it was again so I can take a picture.
Peter Reinhart provided me with some fascinating reading, too, but I soon realized that it doesn't help me at all since our flour uses a different categorization system so I completely ditched following him
