Splitting yeast between batches?

Myself and a friend are very amateur home brewers but are learning quickly. I will be brewing a Dead Ringer and he will be brewing Jamil’s Evil Twin this weekend. Would it be possible to start 1 bag of wyeast 1056 a day early and split the yeast between the batches? How do we know how many yeast cells we are dealing with at that point?

Thanks in advance!

Yes, but you will ideally need more than a day. There are calculators out there for making a starter and how many cells you will end up with, but I’m not much of a scientist. I just pitch a pack into a carboy with 2L starter wort, give it 2 days, add another 2L wort, give it another 2 days then chill for 2 days. Dump off most of the liquid, swirl up the rest and it has been fine for 20 gallon batches.