What amount of washed yeast

The yeast washing illustrated sticky and many other threads and write ups that I have seen show the washed yeast from a five gallon batch in around 4 pint jars and state that one of these jars can be pitched into a starter at a later time to be used for a full five gallon batch. When I harvested from ten gallons I used the same technique just stepped up. I harvested four, one quart jars. I am now assuming I can use the yeast from one of these jars in a starter for a ten gallon batch. Is this Correct? I also did a few one gallon batches and harvested about a spoonful from one of these quart jars for each one gallon. About half of the yeast from that jar has now been used. So by this logic would I be able to use the remaining yeast in that quart jar for a starter for a five gallon batch?
Sorry if this was answered in the sticky. Just thought I would get a case specific answer.

http://www.mrmalty.com/calc/calc.html --> "Repitching from Slurry" tab.

my personal rule is that if the yeast was washed within the past month, i use the above calculator and pitch directly. no starter needed. it's useful to use jars that have milliliter graduations on them so you can see how much of your slurry to add.

if the yeast is more than a month old, i'll use the MrM calculator to figure out how many viable cells i have in my slurry, then use yeastcalc.com to figure out how big a starter i should make (yeastcalc is easier in this case because you can specify how many cells you're starting with... takes a little more effort to do the same in MrM).