First time i did it on a tapajera and didnt get chased and flew straight up, tried again with a tapajera and wasnt quick enough. Go with the pterandon if you can bring one in as it seems quicker than a wyvern now and wear decent armour. As for wyvern milk, there is a second way to raise wyverns without it using a daedon to regen its health once it starts losing health from not having any food