Maybe this will help with the math.
I decided to create this once so I could easily find MS to Tempo stuff .. and vice/versa etc.
http://tools.masteringmatters.com/

I called it a Music Calculator.
I originally wrote this because it seemed like it would be a helpful tool for music studios/artists. Plus it saved time for me personally.

BiaB may throw some curves into the result, depending on the style, but it helps with the actual math.

Make your sound your own!
.. I do not work here, but the benefits are still awesome