With that type of grow, what I have used before (& still do) is these. I'm sorry I don't know what they are called.
I find them at local garden supply places all the time, near the tomato cages. It's a very easy way to LST, & then it's basically it's own scrog system. The grate provides the weight to keep things horizontal, opening up the middle. It's also height adjustable as there are 3 prongs that go into the dirt, so you can put as much pressure as you need. You can see in my picture a Tangerine Dream that is pretty much all set, & has been placed in the flowering tent. Get everything situated before flipping to flower though. You shouldn't have to worry terribly about height if you start training for a couple weeks with these. It will keep things fairly short, while maximizing yield. But you would have to get on it asap. & with these cages you need to provide enough space (the squares are close together). So what I do is train the mains outward, & try to let the middle fill in with the nodes off the mains. This plant, I fimmed the fim, so there are only 3 mains.
You can see that in some spots, I have shoots coming up from slots close together, or even the same slot at the moment. What I will do with those after they come up is take some carefully bent, stiff, electrical wire, & use that to give the shoots separation.
Another thing that is nice about it is that it will keep your plant size in check. If you can string your mains along until they hit the outside of the ring (mine are) & then let them come up, that's about as wide as your plant is going to get. You can also use these to easily train a plant to be a square. I think they are great, because I hate working with a bunch of plants that are all tied into a scrog net.
Incidentally, with heavy yielders like white widow, I can pull close to a lb of dry weight using these things. However, I'm also using a TON of light, from above & the sides, hydro, co2, the whole nine.
That is the moment I realized I'm trying to grow 10 plants so that I can make enough weight. I don't need to. Just grow 4 -5 plants really well. & if you aren't making weight, & it isn't the strains fault, now you know you need to improve other areas of your farming.
