Choose Between:
-5x Julianos: Craftable, decent damage. Good starter set until you farm one of the other setups.
-5x Netch's Touch: Really good, but not the best set for pet sorcs. It takes a long time to farm full divines Necropotence usually though so use this or Julianos until then.
-5x Necropotence: Well I called it, Pet Sorc has been nerfed. Still, it is the top performing set for Sorcs and is still very powerful.

-2x Ilambris: A no brainer for Sorcs, because of the fact we "double dip" into Shock and Fire damage. Also procs from range, which is even better for us.

-3x Moondancer, Infallible Mage or Master Architect Jewellery: Minor Slayer makes this setup best in slot in Dungeons and Trials. It also is a step above Willpower, because you can also continue the set bonuses through a staff or armor piece to ensure no slots of your gear are wasted without MA staves.
-3x Willpower: Useful even more with the amount of Magicka it stacks on to you. You will need 2 Maelstrom staves to make the best of the setup though, otherwise you'll have no set bonus for one of your armor/weapon pieces.

Sharpened Weapons: There is no other practical alternative. The extra spell penetration gained from this trait is so efficient for its slot that it is way too optimal to pass up in any case. It doesn't matter what you find in Sharpened, use non trait staff over precise Maelstrom or Minor Slayer. Sharpened non set outperforms any kind of precise weapon.

Lightning+Fire Staff: Use Lightning on the front for 8% boost to Familiar, Blockade, Liquid Lightning and Meteor damage and use Fire on backbar to use Blockade of Fire.

Lightning+Lightning: Consider this, as Blockade of Storms procs off Balance, which can be a huge benefit to anyone applying point allocations into Thaumaturge like us. Have not tested this much yet, but 1-2 Sorcs can run this setup to good effect.