I ended up sort of finishing my deck with what i planned. It works pretty well. I usually end up having to throw a few basics under the bus. But once a Scolipede or Crobat get going, they take down entire teams on their own.
Crobat does, as you know, 40 damage + 40 between turns + 20 if you manage to have virbank gym out. So basically does 100 damage and if they cant switch out, it will hit 160 by them time its your turn again. Knocking out most things. Plus its ability is night sight. This allows you to draw an extra card if you deem it so.
Giratina makes a good addition to a crobat deck, since crobat has no retreat cost. So if they are poisoned by crobat and you dont want to risk it from taking a hit from something on the bench. You can toss out giratina and with Hex, it can do 50 + 50 if they have a status effect. Or just plain 90 and mill one of their cards for 1 energy more. Giratina is also team plasma, making it immune to frozen city.
Scolipede has poison point. So if they attack it, they get poisoned. Its attack is venoshock, which is 80+40 if they are poisoned. With the additional poison damage of 10 + 20 with virbank. If they cant switch out thats an additional 30 poison damage, making it like 180 damage before its your turn again.
Im still looking for a few more basics to toss in, since i only plan to run 3-1-2 crobat and 3-2-2 scoliped, with 2 giratina. Mewtwo is a pretty good EX if you feel the need for one as it can murder things like Keldeo that just laugh at poison decks. Mr. Mime can protect the bench since you have you carry frail Zubats. Sigliphs are also nice if you have trouble with EXs, as it can be damaged by them. Toxicroak with revenge is also nice, but with two 3-step pokemon in the deck, its probably not a good idea to try and add a 2 step as well. Of course you can also add keldeo into this deck, since its ability is really OP, and having a strong counter to fire is always nice.
As for energy, i have 13 psychic energy with 3 double colorless. The DCE work on all of the pokemon that i propose for this deck, so maybe even 12-4 would be better.