1. All other things being equal, a larger diameter tip (and ferrule and shaft) will cause more squirt (AKA deflection).
2. Some people think they can get more spin on the cue ball with a small tip. I think that has less to do with the tip than with the perceived contact point. When you are spinning the ball, it is the shoulder of the tip rather than the center of the tip that contacts the cue ball. If the center of the tip is in the same place, a smaller diameter of tip will contact the cue ball farther from center than a larger tip, and you will get more apparent spin. So, you will need to aim farther off center with a larger tip to get the same spin for a given speed.
3. Some people like softer tips because they seem to hold chalk better. Some people like harder tips because they seem to be more consistent. I suggest you try a variety of tips. Until you decide on a kind of tip that suits your game, don't waste your money on a layered tip. Also, learn to replace your tip yourself.