After every season (or between the regular season and the super bowl) we record the stats of most of the leaders on each team. They are kept on separate google spreadsheets and we use the query function to generate our top three listing automatically. You can view the full sheets at https://docs.google.com/spreadsheets/d/1GgUXqlj2QyGOvnlC1SF2QlRTCV5kVMehAbNmawfg-cY/edit?usp=sharing or you can use the browser below to view all of our stats (easier on computer than mobile).
In cases where we exceed the maximum limit (for instance rushing or passing TDs) they are either captured after every game or determined mathematically (example, add up all receiver touchdowns on a team and subtract backup thrown touchdowns to determine number of touchdowns thrown by starter).