When to cold crash yeast starters

I put together a homemade stir plate and was using it to make a 2L starter. It's been about 36 hours, and the starter has been fermenting like crazy all day. It's still going strong. I want to cold crash so I can decant the starter, but am wondering whether it is:

1) better to let the yeast finish fermentation and then cold crash, or
2) better to cold crash at high krausen

Either way, I'm not worried and know it will be fine. I was just curious what opinions people had on this.

Here's a pic, it's got a ton of krausen, despite the stirplate!

Cold crash at the end of fermentation.

Cold crash after fermentation has completely finished, plus.

Airlocks are not recommended on stir plated starters. Foam stopper or loose aluminum foil allows gas exchange.