Been making my own hot and sweet italian sausage for several years now. Very easy to make. I have a KitchenAid mixer with a grinder attachment that allows me to attach a sausage "shooter".
I mix 1 lb. of ground pork for every 5 lbs. of ground venison. Usually 1 heaping tablespoon of the seasoning per pound of meat. Used both natural hog casings and synthetics. One thing though, vacuum sealing is a must. For some reason, the casings are very easily freezer burnt, and really affect the flavor of the sausage.