Quote Originally Posted by MattKing View Post

You shouldn't meter through a polarizing filter.

Just take a meter reading without the filter (ideally an incident meter reading), and then apply the fixed filter factor to that reading.

Generally speaking, the orientation of the filter should not affect the exposure setting you choose, although every once in a while you'll be working with a subject where there is so much glare from the (unfiltered) subject that a reflected light reading will be distorted.
Maybe I didn't explain that right..I was using a separate handheld light meter?
Which I had set up to calculate the filter compensation in-meter for me.