MO Foxtrotter bit

I'm new to the Foxtrotting world. I have a new mare that was ridden in a "Foxtrotter's curb" - well, that's what the seller called it. I don't have such a thing and tried her on a snaffle. She pulls hard on the snaffle, but it was a COLD day, she was in a new environment, and she wanted desperately to get back to the warm barn with the other horses. Any suggestions for #1 which bit, #2 controlling barn sour. Thanks from a newbie