You can use manifolding/mainlining, however you would be using this method to force large bud growth rather than total yeild. However if you apply the same care to a LST or topped plant you can attain near sizes with much greater yeild. So in my eyes its a nearly pointless training option for outdoors.
You can top and fim as much as you like, the key is using it the right way to attain a certain type of plant. Topping or fimming multiple times creates more but smaller colas, if you can provide the plant what it needs you can still have big buds on many many colas. But if you dont youll get smaller buds. But at the end of the day your yeild will mostly be no different. With tomatoes i have noticed it the most. If you train the plant to have one main meristem you get big fruit, if you let it have many stems by not pruning its off shoots as much. You get smaller fruit. Weigh it all up however and you get the same yeild in weight regardless of the size. You are better off training the plants to utilize what they have for what you want.
Saying that. I do like to split the apical dominance at least once (4th or 5th node) because i feel energy is diverted more evenly, creating much nicer pathways (branches) for nutrients and water to travel. Also from experience, a single christmas tree has one massive bud and can take precedence and neglect smaller bud sites.
I just topped my tallest colas as the plant was getting too tall, now the rest of the off shoots will catch up and become very similar in height making a nice even plant.