For quercetin I'll go first with the 500 mg dose, once a day.

I realize that Piperlongumi is difficult to get here in Germany. I'm still trying to find a source. On Amazon.de you can only get the dried whole fruits. If everything fails, I'll try those (one fruit per day). If I get the supplement, I'd go for a 50 mg dose first.

I'll let you know once I have discovered a source here in Germany.

And you are right, Quercetin has anti-inflammatory effects mediated by dialing down the histamine response.