Update on day 11:
I ramped up to 0,9 EC. The plant seems to take up the nutrients well. I water every day 1-2 times and try to target 5.8-5.9 pH.
My fear was that I water too much and stunt root development, but the tap root reached the bottom by like day 6 and some side roots are currently touching the side of the pot. Coco really gives gread aeration!
DLI has increased to 17 or so.
I am happy so far.