50/50 methanol-water Vs. water

[GotH2O]

surface tension measures the cohesive force between 2 similar molecules, in this case water. Its this property that allows the little water skaters to move around the surface of ponds. Put soap(surfactant) into the pond and the little insects will drown.
Methanol acts as a surfactant, lowering the cohesive forces between the water molecules, which in theory, allows finer droplets of water to be sprayed from the nozzle. Finer droplets = lower mass = easier to be carried by the air flow = better distribution to each of the cylinders.