Honestly, what's the point of that Zweilous set? Let's take a look at it (relevant) current stats, factoring in the boosted Defenses by Eviolite and the boosted attack by Hustle:
348 HP / 442 Atk / 264 Def / 265 SpD / 152 Spe
This goes along with a pretty notable 20% drop in accuracy. Now, let's take a look at another powerful Dragon, Dragonite. Let's say I'm using Muscle Band Dragonite with an EV spread of 252 HP / 252 Atk / 4 Def with an Adamant nature and Multiscale as ability, factoring in the Attack boost from Muscle Band:
386 HP / 443 Atk / 227 Def / 236 SpD / 196 Spe
As you can see, Dragonite has superior Attack and superior Speed. They have very similar bulk, and that's with Dragonite not having Multiscale intact. Zweilous' bulk is only slightly better (assuming no Multiscale for Dragonite), it has inferior power, no move to hit Steel-types outside of a weak Fire Fang, no boosting move such as Dragon Dance, no Roost, no special moves, every move is instantly as accurate as Stone Edge, etc. Honestly I would never use Zweilous in OU.