Quick questions about my Rubbermaid Grow

So I am just wondering how long I should wait before switching my lighting from 20-4 to 12-12 so I wont end up running out of room in the container. The plants are about 2.5 weeks old from sprouting. Just gave them their first shot of weak nutes 2 days ago. This is my first grow and would love any feedback from this great community!

Some people say that the plant will double in height when it flowers so you could go by that. Or lst and grow horizontal.

Let it get to it 4th set of nodes and then flip. you will want to lst atleast once. when in flower like dan said, it will double to triple in height.

I say flower now . And definitely get some zip ties/pipe cleaners and lst.