Dot Sizes:
Choosing the best dot size depends on the application, and personal preference, but there are a few rules to go bye. If you are shooting the sight at long distances, its best to use a smaller dot, mainly because it covers less target area, allowing you to be more precise. A larger size dot can be used for closer targets, and it can be easier to see because of its size.
The following modules are available, and they simply plug into your C-More sight.
Now you can have the 2 MOA module for long range precise shooting, or switch modules to the 16 MOA dot for short range jack-rabbits, or... well you get the idea.