Trying to cut body fat percentage ?

"Best" is kind of personal, different people do best on different macro balances, and some people get a lot more exercise than other people.

If you're lifting weights (and you should be, if one of your goals is keeping muscle mass), your protein should be about 1 gram of protein per pound of your goal weight, or 1.1g/lb of lean body mass. These are just rules of thumb, you can probably get by with a little less if you don't like eating protein foods. But that's really all you need to keep muscle mass and lose fat -- a calorie deficit, enough protein, and a good full-body weight lifting program.

My protein target is 170 grams of protein, which has 4 calories per gram, so my protein calories are 680 per day. That's 39% of my daily calorie target right now while I'm in a calorie deficit. I usually fill this out with a whey protein shake in the morning, and lean meats like chicken and fish with lunch and dinner (though I like fattier meats too, when I can fit them in).

My opinion is that optimal fat and carb balance depends how active you are. If you're sedentary or only doing light exercise like walking, the carb vs fat balance doesn't really matter that much, and some people do very well with low carbs. But for preserving muscle mass, you should be lifting weights at intense effort levels. For me, at least, that level of effort is best fueled with carbs. I like carbs a LOT.

I have heard people say that they have excellent performance lifting weights on low carbs. So to some extent, I guess the carb/fat balance is just personal preference and whatever works for you. All I know for sure is that low carbs definitely doesn't work for me even at moderate exercise intensity. At all. Fibrous carbs like fruits and green vegetables are loaded with important nutrients and make up most of the volume of food I eat. Fruit, beans and wild rice are great for fueling exercise. So I prefer to eat near the bare minimum of fat needed to meet my body's needs for fat -- about 20% of calories. Then I fill out the rest of my calorie budget (around 41%) with healthy carbs like these.