Draco Meteor/Spacial rend is sortof arbitrary, depends on whether you want to nuke or continually pose a threat. An important thing to note is that when luring Ferrothorn, Draco Meteor will leave you helpless to execute your strategy, so in this situation I'd advise using Spacial Rend. Hydro Pump vs. Surf is the eternal power against accuracy battle, it's up to personal preference. I'd recommend looking at what you require Palkia to hit with (STAB Water move) and determine whether the extra power is necessary.
[EDIT]: lol sweep beat you to it again
"May the odds be ever in your favor"
"WTF HAX NOOB"
The hills are alive with the sound of PS ladderers.
Come over and help out with the Ubers CCAT