I find when i have used shorter rooms that i benefit from shorter veg times. The plants will usually grow vertically for 2 to 3 weeks after switching to 12/12 light cycle. The critical that i grew in the past got topped as soon as there were 6 or so nodes on the clones, then topped both sides after 4 more nodes, and one last time on the third day of 12/12 light cycle. When i switched to flowering the plants are around 12 to 16 inches tall, at the end of the flower cycle they were close to 30 inches tall. that leaves me with plenty of head room for the plants to not burn.
If you are starting to see burn on the tips you should definitely train them away from the bulb. Train the short arms to the center and the tall arms to the outside, like a football stadium.
Your looking real good, and should start to see some nice swelling soon!
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