Hi everyone :)
I've been testing out a Dual Screens Azelf lead and what amazed me was the ease it sets up SR with. I was running Reflect, Light Screen, Explosion and Stealth Rock and it can set up the relevant screen against virtually anything and then lay SR. The only problem is Aero leads, which you have to switch against, but the set helps out against a LOT of other things. Its very similar to the Dual Screener, but its primary aim is SR.
I haven't worked out the EV's/nature yet, although there's a few restrictions. For instance, I'd like to be faster than the standard Naive Infernape, and with some bulk you can take 2 Meteor Mashes and a Bullet Punch from Metagross etc.
Metagross = Probably works slightly better than the standard. You lose to Explosion but that doesn't matter much since you will have set up more than him if he explodes anyway. Like I said before, you can run some HP EV's. For instance, 252 HP means MM will hit you at a max of 41.5% under Reflect. You can't hurt him, but the usual Fire Blast won't let you do much damage anyway unless he sets up Rocks first/ Once you've set up, you can always Explode anyway. Annoying but you get so set up a guaranteed good position.
Azelf = Azelf isn't a great match up. Luckily, most will assume you are as fast as them and SR or U-turn. Obviously Taunt screws you over, if they do use it, so this is one of the couple of bad match ups. However it generally ends up with you both set up and then one or the other explodes. Using screens quickly is bad as it tells him that he can Taunt you.
Infernape = Here you're helped out quite a bit, as long as you're faster than him, which you can easily manage with some speed investment or maybe a Jolly nature. With Light Screen down, Fire Blast maxes out at 37.6% from a Naive Infernape, meaning you will always get three turns to set up or attack barring a crit.
Jirachi = This set doesn't really help you. The old Scarf lead, while kinda uncommon, beats the standard Azelf pretty easily, although it does give you a turn of easy set up after it flinch-kills you. With 252 HP EV's you never get 2HKO'd, so you do have a better chance of setting up.
Aerodactyl = the other lead you do worse against. It will Taunt, so you can either switch or Explode and break the sash.
Swampert = Kind of ambivalent. With the standard you can Taunt him and you're better off, lots will attack or switch. However, running Screens means you can generally set up against him whether he stays in or switches, and should give you a turn at least to finish set up or Explode against the thing which comes in. To give some perspective, CB Scizor's U-turn won't KO you under Reflect, so you're basically good.
Heatran = this might be slightly better for this set. He can 2HKO the standard lead with Fire Blast from the Shuca set, whereas with Screens down he can only 3HKO, giving you time to set up and Explode. Or he can Explode, giving you a turn of set up over him.
Machamp = This is a decent plus. Rather than running Colbur, which is kinda useless otherwise and leaves you open to loads of other powerful attacks; or LO, which again means things like Heatran can OHKO you; here you can reliably beat him if you run Leftovers, since he can't 2HKO.
You lose to Roserade, but it helps against Mamoswine, Dragonite etc etc as well.
So, I was thinking this kind of thing :
Azelf @ Leftovers (means you always beat Machamp).
-SR
-Reflect
-Light Screen
-Explosion (or U-turn, letting you break the Sash on Azelf and Aerodactyl).
Please help me out with the nature and EV's. It needs a fair bit of speed to beat milt and a fair bit of bulk too, so 252 HP / 252 speed looks very fair with a Jolly nature.