EmblemLord it's clear from the calcs that there is some degree of redundancy in the number of SpA EVs - let's not forget that if Ray has to use VCreate, it's dropping its defenses; even if it doesn't use VCreate and uses something like ESpeed first to break the balloon (if it's somehow surviving the Moonblast in return), it's taking LO recoil. So shifting some SpA EVs to Def would solve the "OHKOed after SR" issue.
However ...
I tried and tried to make Air Balloon or at worst Shuca Berry [something] work. The problem is that you fold to all-out attacker sets. If Ray is using 4 attacks, then unless you manage to switch into Earthquake, you are dying next turn to that move. Not good.
For the record here's the best partial check I could come up with:
Rhyperior @ Shuca Berry
252 HP 252 Def Impish
Earthquake
Ice Punch / Stone Edge
Something
Something
+2 252+ Atk Life Orb Rayquaza Earthquake vs. 252 HP / 252+ Def Solid Rock Rhyperior: 357-421 (82.2 - 97%) -- guaranteed 2HKO after Leftovers recovery
+2 252+ Atk Life Orb Rayquaza Earthquake vs. 252 HP / 252+ Def Shuca Berry Solid Rock Rhyperior: 178-211 (41 - 48.6%) -- guaranteed 3HKO
+2 252+ Atk Life Orb Rayquaza V-create vs. 252 HP / 252+ Def Rhyperior: 213-252 (49 - 58%) -- 97.7% chance to 2HKO
+2 252+ Atk Life Orb Rayquaza Extreme Speed vs. 252 HP / 252+ Def Rhyperior: 95-112 (21.8 - 25.8%) -- 2.4% chance to 4HKO
0 Atk Rhyperior Ice Punch vs. -1 0 HP / 0 Def Rayquaza: 216-256 (61.5 - 72.9%) -- guaranteed 2HKO
0 Atk Rhyperior Ice Punch vs. 0 HP / 0 Def Rayquaza: 146-172 (41.5 - 49%) -- guaranteed 3HKO
VCreate is functionally equivalent to Dragon Ascent and Ice Punch has same BP vs Ray as Stone Edge. So: bring Rhyperior in as Ray SDs, eat the VCreate / Dragon Ascent / Earthquake, and then you get to hit it back ... but so what? If it attacks with VCreate or Dragon Ascent Rhyperior can OHKO back after SR + LO recoil, but if it uses EQ twice (or Espeed followed by EQ against Balloon Rhyperior) Rhyperior can't OHKO back against the 0/0 Ray. In the same way Regirock can survive a hit from +2 LO Ray with Shuca Berry, but can't OHKO back. At least Regirock learns Thunder Wave. Not much of an achievement, and maybe something like "I'll Thunder Wave you with my Shuca Regirock, switch to Yveltal to take your EQ (I hope to God you don't suddenly decide to use VCreate, or my Yveltal's dead) and then outspeed, live the ESpeed and KO with Foul Play" will work, but to take so much damage answering this one sweeper is not very reassuring.
EDIT: That said, Ray can't run everything, and there should be counters (not just checks) to some of its individual sets, e.g. physically defensive Skarmory walls SD Ray with ESpeed DA EQ, and if SD Ray drops EQ for VCreate, it would be walled by e.g. Rock Arceus.