How to properly gear compensate for short crank arms?
Being able to easily compare gearing across bikes with different crank lengths is the main reason why Sheldon Brown advocated switching to the proposed Gain Ratios system for expressing bicycle gearing. Gain Ratios measure gearing in terms of movement of the pedal rather than rotation of the chainring. You can use his popular Gearing Calculator to check it out. The other systems are more or less racer-myopic and force you to do additional math when different length cranks are involved, but yes you've got it as far as how to do so.