Ok, i'm going to bump this. For those of you may know, there has been new effective ways to efficiently grind pokemon by hacking. The answer is using BOTS.
I can confirmed it works.
https://gyazo.com/4b87de6ef3a0632ffc24b718bda45216
The bot I used is necrobot
I can confirmed it works.
https://gyazo.com/4b87de6ef3a0632ffc24b718bda45216
The bot I used is necrobot