FIM does not track file size from anything that I've seen. Therefore you wouldn't be able to create a rule based on the data from FIM. The connector settings you're referencing are the types of actions you would like FIM to monitor, so you can either see a file created or not by selecting the appropriate setting.
It's possible that another tool you have, or Microsoft File Auditing would track this kind of information. If you can get an event with file size into the LEM it would be easy to create a rule from there.