While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
Most open gun shooters use 8 MOA. I use 8 myself. IMHO, I find that the red dot covers the target if its larger than 8. I am talking about my preference. Other open gun shooters may disagree.
Just my 2-cents.