If the towel method was working for you, why change it?

Don't fix something that isn't broken! As for overwatering, I doubt that's the cause because you can technically germinate seeds in a glass of water.

Lights, you dont have to worry about. In fact, seeds and tap roots hate light. Keep the lights OFF of your seeds!

Are they swelling up at all? Well.. you said they were in rockwool, hrm. How deep were they planted?