I am not able to calculate the amount of slurry needed at the moment but I can later if you need me to.
In his blog (and somewhere in this thread) Woodland references not paying much attention to the decrease in viability as a serious thing.
The 1B per mL is a SAFE estimate but it all depends on how clean the yeast is and what type of brew (AG, extract, etc... ) that it came from.
If there is a lot of hop and protein debris then the # can be that low.
I safely estimate 1.5B as a conservative estimate for my process, but that is just me.
Thanks for the response. I guess my concern is more around viability. Mr. Malty shows the viability dropping off quick. Others suggest it doesn't happen that quick. The formula provided in this thread I believe would say I have 67% viable yeast at two months. I guess I would like to know what the consensus is on viability. My thought is since I have a sanitized environment at 38F where the yeast is stored, I should assume my viability should not drop that quick, but perhaps I do not understand yeast that well.