I'm working on brewing an Imperial Stout and using a liquid yeast (WLP-007). Beer Smith is telling me that I need about 300bn yeast cells. However, it says I might get 180bn. I'm usually not a stickler for details but this is a big enough difference that it worries me. I bought 2 packs of the liquid yeast and made a starter (rougly 0.75L). Beer Smith says I should roughly have a 1.6L starter (I only have room for 1 liter though...).
Would it be safe for me to pitch this yeast on brew day, buy two more vials, do a starter for that, and then pitch the second starter a couple days later?
Another option might be to hold the chilled wort for a day or two, make the right yeast starter, and just pitch the correct amount.