I can tell you what didn't work for me with U. multifida. I scattered the seeds on wet sphag about 2 months ago and have seen nothing. I have since heard that a heat stratification might work to help simulate the Australian summer but can't say for sure.
I will shortly be recieving seeds of U. tenella and plant on treating some of them with heat and some with smokewater.
For the most part I have given up hope on mine. They are still sitting in their pot but is I don't see anything soon (end of April at the latest) I'm going to write them off as a loss and use the pot for something else. I fugure 4 months is more than enough time to get something, especially considering most Utrics sprout really fast