I've been looking over some cards and I noticed that a few of the damage reduction cards apply before weakness and resistance, which means their effect is essentially double against Volcanion. For example, Parallel city's red side reduces fire, grass, and water poke's damage by 20, and shield energy reduces damage by 10 before weakness. If you have Garbodor out, Parrallel City, and 1 shield energy, that's 30 damage reduced, 60 after weakness and they can't use Volcanion EX's, or Flareon EX's abilities. So a Baby Volcanion can't OHKO M Scizor, Volcanion EX would need a Fighting Fury belt to OHKO M Scizor, and Flareon EX would need 5 fire energy to OHKO, but it can't use it's ability.
Maybe you run a high stadium count with maybe 3 Parallel City and 2 Reverse Valley with 4 shield energy the match-up isn't an auto loss but more of a 80-20/70-30. Running two Lysander would probably help since Volcanion tends to run a lot of non-ex basic attackers and of course for Shaymin OHKO's. Also, Parallel city is already really helpful in other match-up's to get rid of Hoopa's and Shaymin's, and against Mega Ray, so running 3 isn't that bad of choice anyway.
I'll test out a 1-1 line of Weavile with 2-3 weakness policy. I have a feeling that it's going to hurt consistency too much to be worth it.