If you get rid of the chonkers that are blocking light to inner nodes, you'll start developing a nice even canopy.
Also, if you haven't topped it yet, I suggest you do so soon. That's another way to make the inner and lower branches try to catch up to the top of the plant and add even more to the top canopy.
As far as flipping to flower goes, that's up to you. If you do what I suggested, top and defoliate, you'll want to wait a few weeks to a month before you flip them into flower.
I hope this helps.