Yes, changing grips takes at least 3 weeks, it did for me at least.
I changed my grip to more of a "tennis grip" when I was 15 years old and a nationally ranked tennis player. I played both games a LOT during the time and kind of "molded" them together.
I incorportated most of my other techniques in 1991 and 92 after learning from a guy that trained snooker champions and Hank Haney, the Golf Instructor(formally with Tiger Woods). My techniques favors a cross between the "open stance" of snooker and more closed stance of pool, only with mine the LEFT foot parallel to the "Line of the Shot" (I don't claim to have invented this :wink

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I use the Left Foot to aim with as stange as that may seem. Without getting "too involved" I'll say I strive to NOT change my upper body angles, so to "cheat the pocket" or favor the "over cut side" of the pocket I'll turn my left foot slightly.
My left foot is indirectly connected to my cue and the "Line of the Shot", so when I turn my left foot it has a "chain reaction" that moves my cue/aim slightly. Therefore if I'm cutting a difficult shot off the end rail to the right, I can point my left foot slightly to the LEFT and know that I'm going to slightly overcut the shot.
This means a lot because then I can
play a speed to the shot that gives me the best chance of getting "safe". I've said many times if I'm not going to make the shot I want to BE SURE I over cut it. This is how I do it and it's a effective weapon,
responsible for winning many games. 'The Game is the Teacher'