@Monoloco, What I now did is: transplanted one to a bigger pot and the other stays in the can.
On the tranplanted one I will be using mainling and the beercan one nothing.
I'm excited to see the difference in the end :)
@Sweet_Seeds,
I will transplant one to bigger pot and let the other one grow on in the beer can.
It will make for a good experiment ;)
Thanks for your advice!