Bend it over from early on. I like to keep the growing tip. The plant will grow like a forsythia bush if you keep it bent over. You will also utilize the light much better than letting a plant grow sstraight up. All the side branching will be like the main growing tip from an untopped plant.
Ive got a 10 years old Super Silver Haze mother plant that will get 20-22oz a plant, indoors under a 1000w Hortilux HPS in a 20 gallon container, vegged for 60 days. It also stretches like a mofo in veg, and I specifically look for strains that really stretch alot in flowering. I start the clones under fluorescent, or use the light from the 1000w HID, but keep the clones 4-5 feet away from the direct light. Clones dont need much light, and cant take much light or they will try and grow, instead of making roots, and quickly dehydrate trying to grow. After they are rooted I put them under 1000w HID at 24 inches away, and let them frow towards the light. And if I start seeds, I also use a 1000w Hortilux, from seedlng-finish. I also have a 12 years old Barneys Farm G13 x Haze mother that will produce the same and 60 day veg. This was IMHO before BF sucked. Now they suck compared to when they went all feminized, and then went back to regulars. The G13 x Gaze isnt the same as it was 12 years ago. But these 2 particular strains, vegged to the max, in 20 gallon containers take up a complete 4 x 4 area for 1 plant. You can get 1-2 extra around the perimeter in 5 gallon containers. Using 3 lights you can get 1 under the light. I in between the 1st and 2nd light. 1 under the 2nd light. One between the 2nd and 3rd light one under the 3rd light So 5 plants under 3 lights in 20 gallon containers. I go 83oz out of 3 lights, and 5 in 20 gallon containers, and 3 in 5 gallon containers. 2384 grams out of 3000w. So about .794 grams per watt. Also no CO2, but really great fresh air exchange. Im more than happy with the GPW. Also plants were done in 63 days, so I can do this almost 6 times a year. 13 days short of 6 times a year. Thas about 31.1lbs a year at 6 times a year. Out of 3000w of HID.
I bent every plant except the ones in 5 gallon containers. Soil Medium was Promix BX. Not all straind will come anywhere near these numbers. Has to be a fast growing, very branchy, and large stretch plant. Ive got some pure Indicas that wont get half that. Some lucky to 8oz from each lant. and is a waste to grow them in 20 gallon containers. The SSH, and G13 x Hz will completely fill a 20 gallon container with roots. I veg in 5 gallon, and at flip transplant into 20 gallons, and at flip they grow 4x their size. Sometimes 5x. At there fastest growing they use 4- 5 gallons of water every 3.5 days at 83f temperatures. I also have 5-7 box fans going, and make sure every plant has movement. I also shake my plants at least 1 time a day, and bend around on the branches to make strong stems. I veg 24/7.