I have a question, I have two small ones that I wo...

I find that topping or filming is the best to do. Just make sure you have at least four nodes up to top. I have plants that are 7 weeks old. They're 20 in tall and 34 in wide. They've been topped eight times. Their yields are about triple what they normally are.

Mainlining (or sometimes called manifolding) is a more drastic form of training that involves multiple sessions of topping branches to build out an even and equal framework for your plant. It takes a lot longer than basic LST training because you have to give the plant time to grow some between toppings. If you're wanting to do something "quick" then stick with basic LST to break apex dominance.