I just caught a Modest Palkia with the following IVs:
HP - 9
Atk - 28
Def - 24
Sp Atk - 26
Sp Def - 23
Speed - 27
Should I keep?
Naive is fine (allowing you to run a more powerful focus punch), and is probably preferable to hasty because you can take Groudon earthquakes better. I have a 26/x/22/29/30/23 modest Palkia after 3 hours of soft reseting with a modest synchronize Abra.