If we have only details of number of concurrent users that need to support the website/application , from that how to derive the Iteration pacing and think time options from Run time settings for each script.
If your customer's statement is - 100 users is my peak load, ask him - for how long?
What do you get here? - I leave it to you.
Apply little's law.
Total no.of users = Throughput * Response time.
Now since your point of applying the law is at user level, the response time is a sum of wait time + user time.