Ooo, sorry, was not aware of the change until just now. In that case, maybe:
- Protect / Attacks
Slowbro/king (something slower than Ampharos that learns Trick Room and Role Play)
- Trick Room / Role Play (from Gen IV tutor) / Attacks
I just thought Trick room was the way to go because the EVs invested in defenses may make it easier to set up and survive (since as stated, in order for the boosts to be present, both pokemon must be alive).
Turn 1: Ampharos Protect. Slowbro Trick Room.
Turn 2: Slowbro (now faster) Role Play boosting Ampharos Special Attack. Ampharos Attacks.
Slowbro's probably good because of its speed and physical bulk for taking earthquakes. (Ampharos's bulk can take one unboosted STAB Earthquake from most users as well I believe - like Jolly Garchomp Earthquake does 95% max to 252 HP / 4 Def Ampharos).