Proportion of MySQL variables
There is one serious effort to do this - it can be found here. Check out the warning though 


  WARNING
  
  It is extremely important for you to fully understand each change you
  make to a MySQL database server.... &amp;c...


It is virtually impossible to factor in all variables - at the end of the day, it comes down to MySQL expertise. The author (Major Hayden) is a principal architect with RackSpace, so one can assume that he has some expertise.