Estimating number of cells in a washed culture

So I'm making an imperial IPA this Sunday and was going to make my starter with some washed 1056 from a red rye I made about a month ago. I harvested the yeast using the procedure described in this forums stickie. It was my first time harvesting and the 4 pint jars have a nice slurry on the bottom. My question is how do I know how many cells are there? I was going to make a 1L starter with two of those jars for a 1.083 beer. Does this sound good or am I under pitching / over pitching?

 

This thread should give you the information you need, or at least a start when also looking at pitch rate calculators.
http://www.homebrewtalk.com/showthread.php?t=519995