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.

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