Well, that really depends on who you talk to. Everyone has different opinions. I personally see no reason to put grains in the food (unless there is a medical condition or grain free dry foods don't sit well with your dog) and believe that they do more harm than good when in a diet.
Most of the time in my opinion grains are there to act as a cheap binding agent and something to help with the protein.
For meat to veggie percentage, well that's another one no one ever seems to agree with. Some people believe that dogs need no vegetables because they shook out the stomach contents of prey and didn't eat them. Others say the opposite and give their dogs a lot of vegetables.
I'm in closer to the no vegetables. I give about 5% veggies in the raw diet I feed and that seems to have been working so far. Sometimes they might get 10% and sometimes none though, it's always changing and hopefully balancing over time. And that's what raw diets always come down to, balancing it over time. Not worrying that every single day the dog gets the correct amount of organ, muscle, meat, bone, and vegetables.
So if you want to go with a raw diet( recommend) then it's really up to you and the your research and opinions how much meat, and vegetables you want to have in it.
Are you looking at doing a raw diet or home cooked one? Just watch out because home cooked diets are a lot harder , at least in my opinion, to balance than raw ones and I personally think they aren't quite as healthy or natural.
I have yet to see a dog that doesn't like the raw diet. Even my friends dog that is as skinny as can be and will go days without eating gobbles up the raw food I give him.