I skimmed and used the highlight tool, especially for key terms, quotes run-on examples, names, strong emotions, contrasting facts, etc
After you do enough RC practice, the questions that are asked are relatively predictable. Making efficient use of the highlighting tool can make detail-oriented questions easier to find and save you a lot of time.
You can see the text and the questions at the same time. So you can combine this with the Search and Destroy method too.
If you're a slow reader, I highly recommend you practice reading scientific articles! DAT Bootcamp has daily recommended ScienceDaily articles for practice.