We used to put a 5 gallon bucket under the supercharger drain on the R2600's and pump untl there was a steady flow draining out of the supercharger before we cranked with mixtures at cutoff. Once it fired and began chugging, we'd watch for less and less smoke and as the speed increased and the roughness decreased, we'd bring it into operate off the mixture rather than a flooded supercharger.
You're quite correct that one must respect the character and changes that may takes place with a given engine's operation from one season to the next. In many cases, particularly in a light piston installation, resetting the idle mixture seasonally is a very good idea.