The last batch I made was a while back and they turned out a little on the lean side.
I used a whole pork shoulder and a piece of pork belly about 1/2 the weight of the shoulder after it was boned out.
Next time I make I will use 50/50 shoulder and belly.
For seasoning I just used salt and pepper to taste. I ground up a small test batch using the ratios above and did a test fry of a patty to check my seasonings.
The wife's Kitchen Aid got a good workout....