What Happens To Roots In Flood And Drain? How To Move Plants?

For my first grow I thought I'd do DWC, but then I realized I can only fit 9 5gal buckets in my tent(4'x4'), but I have 10 seedlings so I have to rethink my veg setup. I think Ebb n' Flow (flood and drain) is the better option for veg. That way I can take out the males and then use DWC for flower.

But I'm kinda lost as to what happens to the roots as they grow out. Do they just float around? If I use hydroton and then place net pots on top, how do I prevent the roots from entwining all through the hydroton? I keep hearing everyone say how they are able to move their plants around with flood and drain, but I can't see how that's possible once the roots get big and long? Also then how do you move them into DWC for flower??

Sorry if I'm missing something obvious here, but I've read some guides yet I haven't read anything about what happens to the roots as they grow, or how to move plants around.

Thanks

Use net pots. The roots will be air pruned.

Use pots then you can move them...what beagle said