I don't smoke loins. I peel off the blue skin and cut the loin into 3/4" cutlets. I salt and pepper them and throw them into a hot, dry cast iron skillet. Sear them on both sides. This usually takes a couple of minutes on both sides, or less. They need to be rare. Venison has so little fat.
Before I start the venison, I make a Cranberry-Port wine reduction sauce. It is buttery and the tartness of the cranberry with the sweetness of the Port work wonderfully with the venison. My stepdaughter, at 9, tasted this for the first time some 15 years ago. She ate it up and told her mother, the next day on her way to school, it was better than McDonalds. I don't care for McDonalds anymore but coming from a 9 year old, that was a pretty kudo. Anyway, I smoke the hams with Lowry's seasoned salt, lemon pepper and Italian dressing. I rub them and then marinate them in the dressing. 4 hours is good. If you let them go for 8 hours, the Italian dressing turns the texture of the meat to mush. It is tender but has no texture to speak of. I am smoking one now along with a turkey. Anyway, just thought I would throw a different way to serve loin other than smoking or deep frying...