My try-out is now rising.. in my cellar with a temperature of around 10-12°C. I'm planning to let it rise very slowly in there for another 5 hours.

Looking at your proposals and with some extra research, I went for this combination;
- 250 g flour - 100 g lukewarm water - 10 g fresh bakers yeast - 25 g olive oil - 5 g salt
As you can see I weigh all of it, so it's all in grams. The yeast is 1/4th of a package, which is 42 grams, fit to make a normal 1 kilo bread.
I took care not to let the salt get in direct contact with the yeast. I kneaded for around 10 minutes, Et voilà, looks like more or less the amount I'm needing.
The dough is in a glass bowl that I rubbed entirely with a few drops of olive oil. It's covered with a kitchentowl that is slightly moistened.
This is such fun! And so easy, 10 minutes and it's done, and, there's that smell of fresh yeast. Can't hardly wait to make the pizza.

This looks like the portion I need. I hope it doubles in volume in the rising process, just enough for an entire baking tray, or a 2-3 persons pizza. But, let's first see how the dough evolves...
Does anyone have experience with rising dough at low temperature? Well, except for the sourdough yeasting like Bishop does?