[QUOTE=. The only sure way ive found of getting rid of the problem, is keeping my rod dead vertical when I false cast, and finally shoot. [/QUOTE]
My advise to you is forget the complexities of leader for right now. The problem is with your casting stroke as manifested by the hook even when you have leader on.
What the rod was doing at the "STOP" portion of the cast when the energy is transferred, is what the line is going to mimic. So if we see the line doing something other than what we want it to do, we should be able to identify the cause and correct it. Follow that back a little further to what was done by the arm/body to cause the rod to do what it did. Now we can change the arm/body motion to make the rod do what it should have and see the results in the way the line acts.
For example: if the line takes a hook to the left just about the time it is all the way out then the rod must have taken a movement to the left. Video tape yourself or have someone watch you casting stroke. Watching the cast a couple of times will allow you to
locate the twist of the wrist that caused the hook. Then all that has to be done is to stop the twisting of the wrist. Keep practicing and remember, it's more fun to practice on water with the possiblity of catching fish than on a lawn.
Sounds simplier than it is but there you have it. When you rod is verticle, you must not be making the final twist.
There's a fine line between fishing and standing on the shore like an idiot.