slowing down a poolish

Greetings

I'm trying to think of ways to slow down a poolish..

I bake once a week, and I use a combination of both the old dough & poolish methods: I always take about a cup of last week's proofed dough, and keep it in the fridge for next week's baking, to use instead of yeast. The night before baking I take the old dough out, keep it on the counter for an hour, then mix it with a 100% hydration poolish that has all my recipe's water and an equal amount of flour. The next day, about 9 hours later, the poolish reaches its peak breaking point (I know this when cross indentations start to show up on the poolish surface) I then add the rest of the flour and other ingredients, knead and proof.
The problem is that this cycle takes about 14 hours. My baking should be ready for my family by 6 pm, which means I should start making my poolish at 4 am! ..so inconvenient. I need to slow down my poolish about 4 hours, so that I can start the poolish at 12 am.

Here is a few ideas that I'll try this weekend..

• keep poolish flour in fridge to use it chilled
• use cold water from the fridge
• use old dough right from the fridge without letting it sit on the counter
• add recipe's salt to the poolish
• keep the poolish in a colder spot (near a window) instead of kitchen counter

Do you think those tricks could buy me 4 more hours?
I know I can just retard the poolish in the fridge, but a container for 2kg of dough plus expansion would occupy much space there, plus I don't know the time it would need to peak in the fridge (any idea?)
If you have any other ideas, please share them with me..

Many thanks.