When to remove seedling from polystyrene tray.

Just a quick one: I usually start seeds in root riot cubes but I had to go away with work so used a polystyrene self watering prop. The seed has sprouted and there's a taproot showing at the bottom. If this was a root riot I would pot it up now. I'm just wondering if I need to let more roots develop to hold the soil together more before trying to remove the seedling (plant magic soil supreme) or can I just take it out now? It's an auto (Fantasmo Express) Don't want to hurt it because it's the only seed I have of this strain. Any help appreciated.

Give it 7 days and look again. Should be enough available nutrition, I think that should do it.

OK thanks, so wait for more root development?