Boeing helped Evergreen design the adaptation. When it operates as a tanker, it carries 200,000 pounds less than the aircraft's original gross weight limit. It can pull up out of a canyon more steeply than current aircraft. It can make effective drops from about twice as high above the fire, as current aircraft.
Due to its size and high performance, it can deliver as much water to the fire, in repeated drops, as ten or more of the aircraft currently in use.
Coulson's Mars, if close to a suitably long body of water can outdeliver it, over a long period, and with greater efficacy.