My first sourdough bagels

Now that my sourdough is live and kicking, i have decided to put them to work. My first project is sourdough bagels.
After searching the web for a few sourdough bagels recipes and didn't find any that really like so I adapt the formula from Baking Artisan Bread: 10 Expert Formulas for Baking Better Bread at Home that I always use.

Leaven
1 tablespoon of my sourdough starter.
125g water
125g Strong bread flour

Main dough
Leaven 240g
Strong bread flour 295g
Water 110g
Diastatic malt 6g
Salt 3g

Day 1
7:30am make the leaven before I go to work
8:00pm mix the main dough with my stand mixer.
8:30pm divide the main dough into 6 portion and shape them into bagels
8:45pm set to prove for an hour
9:45pm Into the fridge for overnight retardation

Day 2
7:30pm remove the bagels from the fridge set let it return to room temperature
8:30pm boil the bagels
8:40pm  into the oven for 20 minutes
9:00pm Bagels are baked.

My Leaven