Thank you Jeff!
The client I was working with have 35,000 employees of which about 15,000 are using the database at any given time. And the system is, by nature, a document search store. Their current SLA includes a response time at 20 seconds. I gave them a response time of about 200 ms.
And since it is related to medical journals nothing ever (or rarely) changes. The data is stored once and then queried every day for 10 years at an average of 30,000 times per day. It is a R/W ratio of 1:100,000,000, so it's heavily optimized for reading since writing occurs just once and read occurs 100,000,000 times during the lifespan of data.
You can use other schemas if inserts and updates are more important than reading the data.