i always forget which is which between mainlining and manifold.. the one that is less extreme is viable, but the other one people recommend some crazy shit to cut off all the foilage and then if you watch those grows it takes 2-3 extra weeks of vege than it would otherwise. So, not that one. LOL.
Do what gets you to your goal with the least amount of wasted resources. It's good to have a target canopy - 'colas per sq ft' - make it virtually impossible to overcrowd that way and you can make a plant that wastes the least of your time and money. Divide that by number of plants, round up or whatever, and make it happen. ~3 colas per sq ft is usually enough to maximize yield. The only time i'd suggest more is for those tall, lanky plants that grow golf ball nugs well-spread out. Those plants need a bit more per sq ft to max out yield.
let's say 'manifold' is the one i prefer of the 2 mentioned above (could be wrong, this is made up non-scientific vocab i just don't respect, lol). A comb of that with topping will do you good. Get everything leveled out before it even starts to grow vertically and makes the rest of the training easy as pie. Keep as many leaves as possible so as not to slow the plant down.