That’s funny because when I sent an email to Florian, moaning about the leaking oil, he replied that they were doing their best to make it suitable for carpet floors, but yet haven’t been successful. 
As we all know by now, all hubs are leaking when oil is used, but I stay with it. Instead of adding 5 ml per year, I add 1 ml every 2nd month. Furthermore, I asked Florian if I can use different oils, like transmission oil (I still had some left from my motorcycle). He replied that almost every oil would be ok.