Hi this is the first go for me and seeking more help. I bought a hlg 260xl a 4x4x80 tent a 6" vent system some ffhf soil and fert. and most important ILGM auto flower mix pack2. So once the seed starts growing how high should the light be above them and does it need to be dimmed? TIA
Hang led light about 2-3ft above and they should be getting around 240 watts hope that helps
The light should be dimmed down and 24 to 30 inches above the canopy.
Ok so from seedling to harvest lighting heights/driver power
SEEDLINGS AND VEG
Light should be about 24 inches above the canopy with driver dimmed all the way. If your internode’s are to compact then you can raise it up a few inches to get more stretch. If the plants are too leggy then you would lower the light a few inches. Always maintain around 20 to 24 inches from the canopy throughout the veg stage.
TRANSITIONING TO FLOWER
Once you flip your light cycle to 12/12…or autos start preflowering…your going to start turning your driver up a little bit every 4 to 5 days. During the plants flowering stretch your going to let them get to within 15" to the light on their own while simultaneously turning the driver up.
FLOWERING
Once your in full flower and your plants are done growing UP, your drivers should be turned all the way up and your lights should be between 12 to 15 inches
LATE FLOWER/FINISH
During the last week or so you may encounter some foxtailing. If so I recommend 2 things…either turn your driver back down to its lowest setting(this is what I would do) or you can just raise your lights back up to around 24 to 30 inches.
Hope this answers any questions you have. Holler if you need something else 
Thanks so much for the tips @Greenprodigy and @imSICKkid I’ll update when things get going.
Thanks for this @imSICKkid
Awesome graph.