Differences in height of colas and the outcome?

Okay. So, you're in pre flower stage. So max ppfd isn't needed. Nor should u lower your light that close as its still a growth stage. Once pre flower is over you can then even out ur canopy by HST'in / supercropping. Also, to slow nodes that are growing more than others. Take a few of their bigge fan leafs off. This will slow tat nodes growth. (But becareful as ur in a stage where any major Defoliations shouldn't be done) but 2 sets of fan leafs off nodes won't cause too much stress it'll slow that nodes upward growth. Really its not a major thing to worry about. DLI, good feeds methods, air flow, temp and no light stress. These things will suit u more in getting a successful grow. After pre flower that's when light intensity comes much more into play. Good