Its been a looooong time, but if I am remembering my high school chemistry correctly, its not the time that limits how much stuff can be dissolved in the solvent. Its quantity and temperature, but mostly quantity. The alcohol, or any other solvent, will have a saturation point. In other words, 1 liter of any solvent, will be able to absorbe a certain amount of canaoils and no more. It wont matter how long the stuff soaks, once its saturated, no more will be dissolve - no matter how long you wait.
The question is - what is that point? Can 190 EverClear dissolve 1 gram of canaoil or 2 or?.I havent read where anyone actually tested that.
I suspect thats why some recommend multiple soaks. By the second or third soak, if the solvent is lighter in color, then you are getting most of the good stuff out.