First successful propagation, now a few questions..

As the title suggests, this is my first successful propagation. After a bit over a month, it has finally started growing healthy roots. Now I don’t really know what’s next, obviously it’s not ready for soil, but I have a few questions: How long should the roots be in cm before it can safely be potted into soil? I’m afraid of the roots rotting! Also, how do I determine how big of a pot the first one should be?

Hopefully someone can help me :) I’m a beginner, so I welcome any tips!

The plant id is: Ficus binnendiijkii