Scott I have a #12 with .5hp motor and I can grind 5lbs in about 2min, at times it is hard to keep up with the grinder. I'm not sure how important the HP rating is unless you are trying to grind up wood chips. For me the #12 is almost overkill.
I used to go to a butcher to grind my sausage meat. They wouldn't do it for me anymore. I grind about 20 lbs at a time and I don't have to cut the meat into small chunks. I am worried that I will have to chop the meat into small pieces and the grinder will take too long so the farce will heat up and break.
Just a small tip to a issue that is often ignored.
I think many users of grinders would be much more happy with their grinders if they kept the blades sharp. I have turned "useless" grinders into OK machines with a ceramic stick.