Rayquaza wants to constantly amass energy, so each attacker you lose will set you back.
For this reason, I'd actually consider running beast ring.
Not sure what the optimal target is, at the moment, but it's something great to grab with Volkner.
Ray doesn't need the energy on it, so it could just be a bench sitter.
Though, it's not something you would need if you're investing into a Vikavolt line.
If you're using Vikavolt, I would actually run Nest Ball, as it places Rayquaza onto the bench, bypassing it's discard ability.
Lance
also does this, but not sure if it's worth your supporter for the turn; I personally wouldn't run Altaria here.
I'd also choose Vikavolt over Magnezone and Venusaur.
Venusaur requires you to attach manually; too slow.
Magnezone would be hard to keep consistent; you need supporters to get the evo, and supporters to get the energy.
Whereas, Vikavolt is self-sufficient once it's set-up, and can get you both types.
It seems like you'd either play Ray this way, or by discarding energy, not both.
So,
Vikavolt | Rayquaza
OR
Rayquaza | Electrode | Beast Ring
Lurantis is also a good option, and may actually be the most reliable of them all...
It would likely be the first version I try~
I just like the Electrode card a lot...
Electrode into Beast Ring seems really neat; since your opponent is put to 4 prizes immediately...!~
It's GX attack is also good, and can even set-up for it's own ability!
Depending on how the game goes, Electrode's ability would also work with Ray's GX attack.