With 11+ levels of rogue you get Reliable talent, which basically means you auto-succeed for certain DCs. I think I have Astarion auto-succeed with 13's and lower.
In my current play through I'm slightly less optimized than Crimsonrider's setup, but very similar - including hotbar arrangement.
This said, I probably won't do pickpocketing next playthrough, I'm ridiculously OP. I've got 6x Disintegrate and 11x Globe of Invulnerability scrolls.
