Hmmm... seems an overly complicated way to do things. With flash, just dialling in your max shutter sync speed ought to be enough. In fact, my D7000 automagically selects my max shutter sync speed when flash is selected, even in full manual mode. Easy. Why would you not take full, manual control when shooting portraits with flash anyway? Controlling the light is more important in portraiture than almost any other genre, IMHO.
Really? So all the effort you go to when trying to balance the light on your subject in portraiture isn't "dramatically affected" (sic) when using a CPL on your lens? Doesn't seem right to me.
No, the OP doesn't mention portraiture specifically ... I did when I commented on the most common use for a 35mm f/1.8 lens. Doesn't change the facts, does it? Perhaps we'll just have to agree to disagree on the use of polarising filters in portraiture.