Help! Change of plans in middle of bake!

TLDR: I've made the dough with a levain that was almost doubled, but definitely not peaked.  It's going to retard in the fridge for somewhere around 6 hours.  Then I'll take it out continue at fermenting at room temperature.  What should I expect in terms of how many more hours of fermenting will it need before it's time to move on to the next step (shaping)?

The story: I'm setting up to do my first loaf of bread.  I've decided to start with the "123 No Knead Do Nothing" recipe I found on this site.  Blob, my starter isn't as consistent in terms of always peaking in exactly X hours as I'd like: it's anywhere in the 10-16 hour range.  That's a bit slow, but the house is a bit cold, around 70F.  But he's very consistent that he has a nice 3x or more rise.  So I'm figuring it's time to try a loaf of bread.  I know I need to allow some extra time, due to the cold room and in case it happens to be a day that Blob is feeling on the more sluggish end of his range, and trying to plan around that.

Considering that, I decided not to feed him this morning (he usually eats around 11am&11pm).  I didn't think he had quite peaked yet, anyway, and I wanted to be able to feed him & build the levain in the evening to be sure it would rise enough overnight.  I did so at about 7pm.  At that point he was past peak, flat on top but not collapsed yet.  He takes forever to collapse, though, so I aim for him to have that flat on top look when I feed him.  I've tried waiting until the dough starts to recede and leave the streaks on the sides of the container, and he has stayed in that "flat" spot for between 12-24 hrs after having peaked.

I have a sleeping disorder and my sleep schedule can be all over the place.  So I happened to wander into the kitchen at 1am, and the levain's just barely shy of doubled.  "Damn it, Blob," I said aloud (cuz clearly he can hear me).  "Why'd you choose today to be all super starter?"  Unexpected for him to have risen that much so soon, and I'm afraid if I wait until morning to make the dough he'll be far enough past peak and that will slow down how fast the dough ferments even more on top of the cold house and I won't be able to have it done in time for dinner.  So, I decided to go ahead and make the dough, and throw it in the fridge to retard over night.

I'll be up around 6 or 6:30 in the morning, and take it out of the fridge then, and proceed with the recipe.

So, my main question:  I've made the dough with a levain that was almost doubled, but definitely not peaked.  It's going to retard in the fridge for somewhere around 6 hours.  Then I'll take it out to continue at fermenting at room temperature.  What should I expect in terms of how many more hours of fermenting will it need before it's time to move on to the next step (shaping)?

Any and all advice on how to know when to move on to the next steps (the shaping step, and also after shaping, how to know when it's done proofing and ready to bake) will be greatly appreciated.  I've read & read the forum & watched videos but still don't feel confident about that part at all.

Thanks in advance for any help anyone can offer!