After 4 weeks of keeping my seedling alive with standard LED lights and occasional sunlight my tent arrived. The plant was moved into its final 15L fabric pots and placed under the grow light. Around 140W at 30cm distance to start with.
My Mimosa is sharing her tent with one other plant for the entirety of this grow.
As I did not really have control over her growth so far, I consider the move into the grow-tent as the starting point for her vegetative phase.