The key idea is one channel size keeps it's VERTICAL distance always. From 1 to 1p or visa versa remains a constant distance no matter what the angle of the channel. The 2nd thing is, when a channel breaks into future data then you have to go back to a reset point so the channel follows the edges of the data and doesn't break through it. (usually key bottoms or tops are the set points). This method is very accurate IF you can determine the correct LEAD or 2L point...which is harder than you think.
T=top B=bottom. The formations are bbt , btb, btt , ttb, tbt , tbb. Three point hits in a channel is what you are looking for. Sometimes there are 4 bounces in a channel (from one side to the other) instead of 3.
The 2 best formations are bbt and ttb. They are usually steep moves and the 2L or lead points are usually set close to the starting 1 or 1p.
There are other channel ideas that I have published. This is the method that I trust the most.