The question should be closed as too localized.  The [Can you help me with my capacity planning?][1] was created to give some general advice about benchmarking and planning as an alternative to close questions  as too localized.

As you mentioned in your answer, there is simply no good simple answer.

About the only thing you can say is 'it depends', or tell the person the general process for how to test and find the solution themself.  

  [1]: https://serverfault.com/questions/384686/can-you-help-me-with-my-capacity-planning