When smoking summer sausage, I use the hi mountian mix, but go through one more temperature step. It seems to help keep the casings from getting dark close to the smoke chamber. When they do discolor, the meat is not affected, and it looks fine when you remove the casing. I smoked 90 3 lb. sausages over a five day period. The Cabela's sausage stuffer, and meat mixer is a bit pricey, but if you are processing a lot of meat it is well worth the price.
Dave / Rhino