I find this completely insulting.

Read the OP's comments about being lost amongst all the discussion about the "science" of it all.

And unfortunately, your high-school maths doesn't take into account a number of other factors, including the rider's weight, load, the inclines expected, tyre width and inflation, headwinds, and fitness and strength of the person in question.

The OP really needs to experiment. For the cost of a 22T and 24T granny, he can take a trip out to the Kimberleys with his car, and do some riding there and find out what really does suit him.