Well, You guys all make it so complicated. I just take snippings about 5-6" long from a coat hanger, bend the end to make a hook. and when my clone is small, i bend over the top, putting the hook just below the top node and put my hangar hook in the soil to stay. I keep training that first top sideways, until it hits the side of pot, and let it grow up. Well the point of doing this is that the under branches of the plant start to think they are the top bud since they are receiving so much light.
And well, the "underbranches" start to grow straight up as if they were the top, and then I simply repeat. I get my hooked coat hanger, and i bend over and train the direction i want that new branch to go. I end up with about 10 coat hangers in each pot. The resutls .. well, see for yourself, i get plants this big every single time in a months time.
Bending over makes it SO SO much easier to take clones from, and then of course, gives you the 10-12 top colas/branches that you want. It doesn't hurt that plant at all like topping does.