I have some grassfed beef roasts that have been too tough to eat on their own, even with the very low and slow approach, so I started grinding some of the meat and turning it into meatloaf. The results are awful (dry, unpleasant texture), I think because it needs some fat. I have some pork fat I thought I'd grind in with the next batch. I just don't know what ratio I'd want to aim for. Any suggestions? If it helps, I usually cook 6 pounds of hamburger at a time. Thanks in advance . . .