Actually EQ seems as a good option for the LO set! Here are the most notable calcs:
- EQ vs 252 HP Jirachi: 43.06 - 50.74%
- EQ vs 252 HP Ttar: 39.85 - 47.02%
- EQ vs 252 HP Heatran: 85.19 - 101.29%
Latios needs 24 Atk EVs to OHKO 252 HP Heatran after SR. Seems good enough for AC on the LO set.
EDIT: A Naive nature was used btw.