Dont think BARF diets are an exact science mate, my dogs are between 50lb - 60lb and they get around 3lb of meat a day either chicken carcasses, beef tripe, beef mince and meaty lamb bones when I can source them. I also started to give them Eukanuba a couple of times a week about 6 months ago and have seen a difference in them since I've been doing this. Once every 2 weeks I also leave them for a full 48 hrs without any grub.
I mince nothing, aslong as the bones are completely raw your dog wont have any problems, bones are one of the best parts of a BARF diet IMHO. My dogs are wormed every