You should but Bartering and Persuasion on the same character not Thievery. Persuasion at a little influence on shopping too. Don't think that thievery and Bartering have any synergy. If you get caught thieving, you lose attitude anyway.
If you had played the game past Driftwood, you would already know that is BAD ADVICE.
Each character should take one and only one civil skill until it is maxed out, you don't get enough to do otherwise.
Splitting points between Bartering and Persuasion means you are guaranteed to fail Persuasion checks later on you otherwise would have stood a chance of passing.
