It seems that what I want to achieve seems impossible but I still think asking might be worth it.
I would like to have :
"option + double left click" to make the window under the mouse half of the screen (left or right depending on mouse position)
"option + triple left click" to make the window under the mouse a third of the screen (again side depends on mouse position)
Here is what I have made so far for the right side but triple click seems to trigger both and the window being resized to half the screen seems to take precedence.
Nice, that's useful. Unfortunately, BTT does not seem to block the predefined action of an app. So it triggers both actions. But I can change the modifier, all good.