Bulk Fermentation: Help, Please How to know when it's time to divide

Bulk Fermentation: Help, Please How to know when it's time to divide

Hello Gurus,
Today, shut in by the snow I am trying a new recipe.  !00% sourdough 50% whole wheat. I mixed the preferment yesterday evening and dough today (Hamelman’s whole wheat levain).  Embarrassingly, I forgot to do stretch and folds until I was 2 hours into the bulk ferment.  Oops!! 

However, my rube-goldberg inspired proofing place is still cooler than any bakery so it still wasn’t far along in rising when I remembered. (I was prepared for this  slowness as many have said his times for everything need to be increased due to temperature differences).  Still, I panicked, did my s&f  set my alarm and did another according to recipe 50 minutes later.

You all talk about paying attention to the dough and not the clock… so that’s what I’m doing.  The recipe calls for 2 1/2 hour bulk fermentation, I’m past the 5 hour and I’m not yet panicked.  I’m just seeing a nice rise now and bubbles at bottom and sides (container is plastic).  My gut tells me to go ahead and divide.  I’m gonna pay attention to that unless someone talks me down in the next 15 minutes.  Don’t want to over proof at any time.

Thanks in advance.  Sorry to be so verbose.

Source: Fresh Loaf