Hey Jak, I am starting with Alton Browns 50/50 sirloin and chuck and modifying from there. In the past I've added lamb, pork and now beef ribs mostly because I read the article on amazing ribs dot com. I'd have to say that the addition of beef ribs was really nice but not necessary but nice enough to try again modifying the ratios. It did give it a real "beefy" flavor that was noticeable and next time I am going to cut the chuck back and increase the ribs. As far as grounding round, do you mean the shape of the grinder? Because I just got this one and I like the shape a lot. It made for forming the patties firmly but still loose, almost like a burger puzzle when formed allowing the juices and heat to distribute. I used to use the pulse setting on the food processor (also what Alton Brown recommended) and I'd have to say that this way is much better, mostly for forming and getting evenly cut pieces.