I use 11 liter pots. The lower half is filled with All-Mix, the upper half with Light-Mix. The soil has great volume and I have been using it since my first grow.
The soil was carefully watered with approx. 2.5L of water ~6.5ph so that the organic life of the soil is reactivated.
I decided to germinate the seeds directly in the soil in the final pot because that was how I had the best experiences/results in the past.