Hi Ines!
Many recipes call for Turbinado because of its higher burn point. However, it is really not needed when smoking. Regular sugar will start to burn around 265? and Turbinado burns between 320-367?(this according to an e-mail inquiry on my part).
So, if you smoke below 250?, then the sugar will not burn on you.
Because of the huge price difference, I never use turbinado. I DO cook all my meats at 225? and have done the Carson's method of rib prep....saucing both before, and during the cooking cycle. Never had any sugar burn on me.