I've been doing some reading at mrmalty.com, and am left with some questions.
Assuming the info below is correct, what upper limit of wort SG's would you feel comfortable pitching a 2 liter starter into? If a deviation of 20% is allowable per Logsdon, I'm coming up with upper wort gravity of about 1.064. I realize Logsdon's statement is one of "preference".
1 liter starter = about 150 billion cells
2 liter starter = about 200 billion cells
1 liter starter, then pitched into 4 liter starter = 400 billion cells
The proper amount of yeast for 5.25 US gallons of 1.060 wort is around 225 billion cells if you are pitching 0.75 million per milliliter.
(750,000) X (20,000) X (15) = 225,000,000,000
"Logsdon says, "I try to stay within 20% of my ideal pitch rate and I prefer to slightly under pitch rather than over pitch."