First grow in flowering, looking for any advice

First grow into flowering, I’ve seen pistils for about 3 weeks now but wondering if this stretch is normal? Ppfd showing around 500-600 in the flower canopy but very high on the top bud, is there anything I can do at this stage? I switched to bottom feeding and noticed a huge difference in growth but wasn’t expecting it to stretch this much. Besides the little nute burn on some fan leaves, is there anything else I can do to help the plant? Experimenting with the three plants to see what grow method works for me

Northern lights, broke soil 26/12 Coast of Maine VS1000 at 18/6 cycle Micro, gro, CalMag and GroTek monster bloom