I have tried to use a more configurable plugin for my caching for some time, but don't think I ever fully got my head around it. I decided to change and did a search for reviewed WP cache plugins, and this one came up. So much easier to set up and use, and hence, better results loading already.
Regarding the post above for Tweets not showing, I use a Twitter embed (rather than a plugin), and I'm having no problems. Thanks!