Questions about splitting up starter

Sometime in the upcoming week I will engage in my first attempt creating a starter. I make 1 gallon batches so I've always just pitched a half vial. I plan to make a 1.2 liter starter that is appropriate for a 5 gallon batch, then splitting that up into 4 jars and using each jar for a 1 gallon batch. I don't have a stir plate, so I will be using the intermittent shaking method.

First question: At what point during fermentation of the starter is it ready to cold crash and/or split up? Do I wait until just after the krausen falls?

Second question: do I need to decant the "beer" from the starter or can I just swirl up the whole starter and split that up?

Thanks from a first time yeast manipulator!

I would chill it after 36 hrs., to be sure it has maximized yeast production. Decant the (yucky) beer 90% off, swirl the remainder.