here is a tip:
When you are horde battling for EV's, like for example: Wingull hordes for speed (w Power Anklet).
You can just stay battling Wingulls after maxing the speed EV's and change into another Power Item.
The Wingulls still give you the EV's of that new Power Item, minus 5.
Sometimes I find it easier just to battle the same hordes instead of flying to a different route
You only have to do one horde more to get the same EV's:
Horde + power item + Pokerus
((1 + 4) * 5 ) * 2 = 50 EV's -> 5 hordes for 250 EV's
Horde(max EV) + power item + Pokerus
(4 * 5) * 2 = 40 EV's -> 6.25 hordes for 250 EV's
When you are horde battling for EV's, like for example: Wingull hordes for speed (w Power Anklet).
You can just stay battling Wingulls after maxing the speed EV's and change into another Power Item.
The Wingulls still give you the EV's of that new Power Item, minus 5.
Sometimes I find it easier just to battle the same hordes instead of flying to a different route
You only have to do one horde more to get the same EV's:
Horde + power item + Pokerus
((1 + 4) * 5 ) * 2 = 50 EV's -> 5 hordes for 250 EV's
Horde(max EV) + power item + Pokerus
(4 * 5) * 2 = 40 EV's -> 6.25 hordes for 250 EV's