To get the most out of my LEDs, I try to get the canopy low and uniform so the entire plant is in the "fruit zone." If you buy LEDs, get ones that don't have the ballast attached directly to the light/fixture. LED v. HPS, LED generates less heat; and LED has even less heat when the ballast is a cable away. I can get my 66" Fluence Ray LEDs mere inches -- trying to get them ~10" before stretch -- from the top of the canopy without burning it. With LED, if your plants vary in height, you'll likely see a significant drop off in yield on plants further away from the light, even though your light meter puts them above the minimum threshold for flowering (you'll probably want to exceed the minimum by 2 or 3x).
I experimented with various trellising techniques and now use a combination of (1) a layer of cross-hatched 18 gauge steel wire (toward the top of the canopy) (not essential, only use it in one tent) and (2) cork weights hooked toward the end of branches (start young, remove the weights once the buds are big enough to replace them) (I consider cork weights essential). I prefer topping, adding cork weights, defoliating, and encouraging secondary branches over popular techniques like lollipopping.
