For a naive test, powers of ten work alright. Generally I increase the number requests until it tops out. Lets say your app takes 200ms and you can handle 1000

For a naive test, powers of ten work alright. Generally I increase the number requests until it tops out. Lets say your app takes 200ms and you can handle 1000 reqs/sec, you can use that as a baseline to determine whether you need to throw more hardware at it or work on improving the software.