WP Super Cache plugin settings are in Details (in Install Plugins search on WP Super, and then read details. Have pasted settings section from Details below:
Advanced users will probably want to use mod_rewrite caching, but PHP caching is almost as good and recommended for everyone else. Enable the following:
1. PHP caching.
2. Compress pages.
3. Don't cache pages for known users.
4. Cache rebuild.
5. CDN support.
6. Extra homepage checks.
Garbage collection is the act of cleaning up cache files that are out of date and stale. There's no correct value for the expiry time but a good starting point is 1800 seconds if you're not using legacy mode. If you are using that mode start with an expiry time of 600 seconds.
If you are not using legacy mode caching consider deleting the contents of the "Rejected User Agents" text box and allow search engines to create supercache static files.
Likewise, preload as many posts as you can and enable "Preload Mode". Garbage collection will still occur but it won't affect the preloaded files. If you don't care about sidebar widgets updating often set the preload interval to 2880 minutes (2 days) so all your posts aren't recached very often. When the preload occurs the cache files for the post being refreshed is deleted and then regenerated. Afterwards a garbage collection of all old files is performed to clean out stale cache files. With preloading on cached files will still be deleted when posts are made or edited or comments made.
See the WP Super Cache homepage for further information. Developer documentation is also available for those who need to interact with the cache or write plugins.