>>30544893Assuming a 31 Speed IV, 44 HP, 252 SpAtk, and 212 speed with Modest outspeeds Timid 252 Speed Pheromosa after +2 speed from Gear Shift. If you don't care about beating Pheromosa, 124 Speed are all you need to outspeed Timid Koko.
Fairium Z movesets with Modest are what I've been looking at. Gear Shift, Fleur Cannon, and Flash Cannon/Aura Sphere/Shadow Ball/Ice Beam/Thunderbolt/Grass Knot/Energy Ball (Pick 2). Twinkle Tackle is 195 power from Fleur Cannon, and then by the time you have to actually use Fleur Cannon, you should get enough Soul Heart boosts to offset the -2 Sp Attack drop from using Fairy Overheat.
