Some had mentioned a counter and that is why I came up with it and posted it.
I personally like the counter for its ability to give a ball park number. I chose the cheap counter off ebay so that it would be cost effective. I believe in the KISS logic of keeping it simple and agree with your idea of keeping track of the primers used. To my line of thinking at best the count is going to be close because you are running a lubed bullet thru the sizer again and this throws the count off.