1. The positioning of your mouse won’t matter a lot unless you are a pro gamer.
2. When you are searching for a gaming mouse, there are a couple of things that you should look for besides the mouse being comfortable to use.
You should choose a mouse with a high DPI or dots per inch. You will find companies mentioning that their mouse has a high CPI, but CPI and DPI are the same thing. If you are confused on this, read this article.
You should also check for the IPS of the mouse. IPS is the maximum obtainable speed the sensor can track precisely. Acceleration is another important measure for pinpointing the mouse sensor quality; it’s the max gravitational force at which the sensor can accurately track movement.