If im not mistaken, the orphice tube is in the ac line under the dash that goes into the evaporator and if you have a blockage that could be the cause,.
About the wite smoke when you have to much pressure in the lines that can cause a discharge from the vente.
Next time you run your ac go under the hood and see if the high pressure line going in to the condensor is realy hot if so, you have a blockage. I would also check the pressure switch it could also be going bad.
If you have any more questions or need help pm me or call me my contact info is in my sig.
Cood luck Cory