Converting That Peasant Bread Recipe To Sourdough

I'm not sure if I saw this in my FB or my Pinterest feed, but figured I'd "math it out," and make the conversion necessary to make Alexandra Stafford's (mom's) No Knead Peasant Bread into a sourdough hybrid. 

The breakdown of ingredient list from the original recipe are:

4 C Flour
2 C Lukewarm water
2 1/4 Tsp Yeast
1 Tsp Sugar
1 Tsp Salt

The way I will approach this as a sourdough, for the next batch of bread I bake will be:

LEVAIN:

1 C Sourdough starter (unfed)
1 C Water
1 C KAF Sprouted Wheat Flour

Let this sit at room temp 12-18 hours until nice and active.

When ready to continue building the dough, I'll then bloom the yeast:

1/2 C warm water
1 Tsp sugar
2 Tsp yeast

I'll add the bloomed yeast to the levain, then mix in the remaining 1 1/2 C flour (I'll switch to bread flour for the remainder).

Let sit for 30 min to autolyze. Then add 1 tsp salt and mix well.

At this point, I *could* follow the remainder of the recipe as written, OR divide in two portions of dough (I'll use a digital scale to ensure equal amounts of dough in both bowls), put in a greased bowl and cover with wrap and put in fridge for 24 hours for a slow, cold bulk ferment as I do with nearly all my sourdough bread, and take it out of the fridge for about 1-2 hours before baking.

Bake temp and time is as stated in the original recipe:

Preheat oven to 425, and bake for about 15 minutes, then lower heat to 375 and bake for about 20 minutes more. And as the original recipe states, if the loaves look pale, bake 5 minutes more.