It would have to really be a guessimate. But if you plug in a clean average induction menu into fitday you come out at about 3-5% carbs per day I would guess that of those 2-4% should be vegetables and the remainder be cheeses, nuts, and other sources of fats that contain carbs.

You know, 50% or less does sound reasonable now that I think about it. I mean, 3 cups of salad only equals maybe 4 or 5 carbs, maybe a little more depending on which salad veggies you choose.

I know people who have limited their "other carbs" to 10 a day, then ate as many veggies as they wanted, rounding out to about 20 or 25 carbs total.

If you are having fruit and nuts, then it's safe to assume your not in induction. This probably means you should have a slightly higher percentage of carbs and lower fat.

The majority of your carb based foods should be veggies. They may not make up the majority of your carbs though because they are so low carb. While you may only have a couple servings of nuts and fruit, they would equal higher carb grams then the veggies.

I'd say instead of worrying about percentages of the grams, make sure that the majority of carb based food your eating in a day is veggies, with only a small serving of other carbby foods.