I have always used natural casing from Butchers and Packers, either hog or sheep. I have had very good results from them.
The thing about all sausage is to keep it cold. Period! It cut/grinds better cold. its easier to season and mix, although its cold as all get out. Its help firm up the sausage before stiffing, etc etc .....
After you smoke it ( about 2 hours total max, ya see its all cooked already), into chill. once its rested and cold, then I bag and tag it. Its not hard, its just the most important thing is cold when dealing with meats. When you add rice or a starch you've really got to watch it. Don't want any one to get sick.