I havent done a pork tenderloin yet but i really want to, let me know how it turns out. As for the fatty, you can do whatever you want with it. I have found that some of the basics are stuffed with your favorite cheese, or a mixture of a couple. Vegetables like onions, tomatoes and peppers also find their way in also. As for stuffing, i have found that there really isnt any right or wrong way, but some ways are a little easier than other. I suggest rolling out on parchment paper to about 1/4 to 1/2 inch like a pizzza dough if you will. Rollingout on some surfaces like metal pans cause it to stick and thats no fun, so parchment is a great stickless alternative. From here spread your cheese or veggies or whatever you prefer on top of the flattened sausage. From there, just roll it back up like a burrito and try to keep the stuffing on the inside, a little bit on the outside wont hurt nothin though. Once roled back up, shape it roughly back into the shape you bought it in. From there get your smoker between 225-250 and throw your meat on. At 160 degrees internal, your done, both for the tenderloin and the fatty. Usually my fatties take about 3.5 hours. Just go bye the meat temp and you shoud be good. let us know.
P.S. do you go to bama?