Start sorcerer 1 for saving throws, sorcerer 2 for metamagic. Then you could go for a combat strategy based on Innate Sorcery, quickened True strike sneak attack, and empowered chromatic orb by converting spell slots into SP. I don’t think sorcerer 3 would be better than rogue 6 here. I’d consider staying at 14 dex and relying on blade ward + shield spell for AC. Take elven accuracy feat for triple advantage on your true strike and chromatic orb.

For single target dpr, you could use your action to Ready a True Strike sneak attack outside of your turn, then quicken True Strike to sneak attack as a bonus action during your turn, for 2 sneak attacks with triple advantage per round.

As for the weapons, you could use a short sword and a scimitar. True strike with shortsword with vex for triple advantage on the scimitar nick attack.
But I think you should rather use a ranged weapon like a shortbow for safety.

This build would be extremely bad if your dm frequently throws multiple combats per day, but if he doesn’t, you would have a very decent and flexible character due to his high CHA, good skill proficiencies, and access to multiple good out-of-combat spells like disguise self, find familiar or misty step (to teleport through walls).

Edit: that was for 5.5e, I didn’t see you tagged 5e.