If you're getting a cache hit of 100% at the minimum cache size, great! Keep it that way until you notice the cache hit % decreasing. Think of the recommended cache hit of 95% as a minimum, rather than an optimum. Lower than that, and your users are likely to get less-than-stellar performance as data has to be read from disk instead of in-memory cache. Higher than 95% is gravy. Just be careful to balance that with the cache unsaved % — less is better, since that means the cache and data on disk are being kept in sync better. If the cache unsaved % is frequently more than 5-10%, you may need to (1) get faster disks, and (2) reduce the cache size to force Server to flush data to disk more frequently.
Thank you jbante, I will follow your advice!