@bfcuk, Well, it's more cozy than comfortable, but it's possible if the timing is right. Fortunately, we have another lamp that we can come back to. This only comes in for a few days if its getting too cozy in the tent.
As we don't have enough space available, it's definitely an option to grow four in this tent, but of course each plant could develop and flourish better, if more space available.
In the end we're happy with the decision.