All other things equal, a single wing is more efficient than 2 wings summing the same area.

Change from a 2 blade to a 4 blade, and you will lose efficiency, which means higher amps and more mah used to accomplish the same flight. Not a good direction to move to (IMO), unless you are forced to do so by lack of ground clearance, to reduce noise, or lack of the correct sized prop for your needs in a 2 blade. Adding blades only increases downline braking when the total blade area increases.

Regards,

Dave