Glass Factory help

[HeatStroke]

As many others have probably experienced, recently I arrived at the glass factory during my play through, specifically the series of double battles. After being unable to win for quite some time, I began to look online for ways that others have won, and came across this video:

 

Obviously, this strategy appealed to me because it only required me to catch and EV train 3 pokemon, which I was able to do with a few hours' effort. However, I found that I was still unable to out speed some of Shelly and Cain's pokemon, specifically the Meowstic and Scolipede, despite having near perfect speed IVs and EV training that favored speed for both pokemon. The question I have is whether or not some change was made in more recent versions of the game to prevent this strategy, or if I should try to get perfect IVs, or if I would be better off just trying to beat the fights with the pokemon that I already have. If anybody has any kind of alternative strategy that I could use also, I would be open to those suggestions as well, although if anybody has a reason why the strategy in the video doesn't work with a quick fix, that would probably require the least time investment from me. Thanks for the help!

Edited May 19, 2019 by HeatStroke

[Vanitas]

archeopteryx, krokodile and mega lopunny.

thats how i beat the battles with only 3mons

not sure what you already have...

[Ryuta]

Glass factory gauntlet is the quite a challenging fight depend on the team you have. I pull through using sword dance team combo with earthquake. I'll share my team key player at that point may be it'll help also this pokemon you can found in wild at pretty high level or you can just grind at grand hall it only take me 1.5 hour to grind to cap with the help of lucky egg.

Excadrill - Sand rush (Earth Plate) (Sword dance+Earthquake sweeper)

 - Sword dance

 - Metal claw

 - Rock tomb

 - Earthquake

Talonflame - Gale wing (no item) (Lead for earthquake combo and Shelly killer)

 - Acrobatics

 - Fly 

 - Steel wing

 - Roost

Aegislash - Stance change (Fist plate) (Sword dance sweeper for 2nd and 3rd fight) 

 - Sword dance

 - King's shield

 - Sacred sword 

 - Shadow sneak

Noivern - Infiltrator (Life orb) (Another combo with Earthquake user also shelly killer)

 - Air Slash

 - Boomburst 

 - Dragon pulse

 - Fly 

 You don't have to to choose perfect IV and EV train you just have to pick your team carefully and also try do side quest you'll get a lot of good pokemon such as mimikyu,honedge(both are very broken in my opinion),espurr,etc.