I have instructions on how to make a yeast starter but how do I know what size volume to make for a particular beer?
Use Google, et al, to search for "yeast starter calculator".
The Mr. Malty calculator is popular but they all seem to give fairly similar results.
Drinking: Russian Imperial Stout
Drinking: Pre-prohibition Lager
In-process: Another batch of Pre-prohibition Lager
Next up: Scottish Wee Heavy