I am fortunate to have lots of toys and I am part of another ATV forum. Our ATV's hold 2-quarts of oil. It is NOT UNCOMMON for many on the forum to run up to 1/2 a quart more in their ATV's. Now that is some perspective and you are worried about 1/2 a quart too much in a 6 - 6 1/2 quart capqacity situation.
Its your vehicle and you can and will certainly do what you want with it but I think you are being overly paranoid over nothing.