We make about 100 pounds of sausage every year for our Oktoberfest and usually only cook about 60 so we have brats all year long. My wife loves the weisse brats in Bavaria but has some misguided aversion to eating veal so we make it with pork and chicken breast instead. We normally make about 25 pounds of the weisse brats, 75 of the standard brats. We also make about 5 pounds of the standard into breakfast sized patties and freeze them.
My standard recipe calls for 60% lean, 40% fat, and we use about a 50/50 mix of pork and beef. Packer trimmed briskets are my favorite beef cut to use because it does have plenty of fat on it. Another trick I've learned is to grind the fat separately with the fine disk and the lean with the coarse disk for better texture.
Here's my setup for sausage making:http://www.northerntool.com/shop/tools/product_36989_36989http://www.northerntool.com/shop/tools/product_200004374_200004374http://www.northerntool.com/shop/tools/product_200333527_200333527
These were Christmas presents from my wife and kids, gotta love 'em