[Plugin: WP Super Cache] caching question

is there a way to manually specify which pages to cache?

we have a site that is about 60-70% static pages that should always be cached and the rest are dynamic pages or pages that have various javascripts that perform some data loading or calculations.

we installed wp-super-cache and set it up to cache using php and set up preload to cache all pages.

when visiting the pages on the site the first time the pages did not seem to be cached (loaded at pre-cache installation rate). After the first time they did seem to be cached, although some of the pages with dynamic content seemed to load slower than before.

are we setting the plugin up correctly?

http://wordpress.org/extend/plugins/wp-super-cache/