I originally tasted this recipe at my aunt's house for dinner one night. The gravy is to die for and you can really use any kind of roast you'd like. My husband and I use the Hormel brand tenderloins and my mom prefers a chuck roast. I'm unsure what my aunt used but she directed me to Eating My Words for the recipe. I do add a bit more water to the CrockPot when I make this because we like our gravy around here and it just doesn't end up with enough otherwise. Haven't tried doubling the packets and the water but I probably will next time.
In the comments: are you particular about where you buy your meat or what kind you get? Or do you just get what's on sale that day?