For the average personal processor,I think a #12 is about the best.Plates and knives are reasonably priced and you will probably spend as much or more time cleaning than grinding.Also look for a good size throat on the grinder head so you don't have to cut the meat into little pieces before you grind it.I use an old General small commercial grinder.It's quiet,powerful and designed to grind large quantities of meat.
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~Molɔ̀ːn Labé Skýla~
As Bob Hagel would say"You should not use a rifle that will kill an animal when everything goes right; you should use one that will do the job when everything goes wrong."Good words of wisdom...............