Hi there, i'm a first time ddb x mastiff owner. Buck is 8 weeks and 15lbs (just over 7kgs) Is this a good weight for him? I've been reading up and know that it differs with every dog but was just wondering if this was a good average. Also my vet recommended royal canin junior large which he is doing well on but i'm starting to think he should be on royal canin junior giant. Any advice would be much appreciated, we only want the best start for him.