Ok, for some of you newer to the breed, here is what the Standard has to say regarding the tail--
BACK: Broad it's entire length, sloping downward from base of neck to tip of tail, with sufficient saddle feathers to make, without break, a continuous unbroken line from base of neck to tip of tail, which is a characteristic of the breed.
TAIL: Long, broad, well-spread and carried below horizontal. The distance between the base of the tail and the end should be longer than between the base of tail and beak.
Sickles and Coverts -- long, abundant, drooping; many dragging on the ground.
Bruce- The tail angle being discussed is when the birds head is upright, not down when foraging, or when the birds are excited, etc. Think of the bird in a "normal' pose, as in all the Standard illustrations. Perching, cold, wet, or sick birds will have lower tails, as will older birds. Younger, excited, molting birds will have higher tails. So there is some degree of movement possible in tail angle, but, when relaxed and upright the angle should be such to give you the unbroken line as described above. There is a lot of variation possible in the tails without being disqualified, but, the Standard is clear on what the ideal tail is to look like.
Cubalaya- You have made great progress with your birds over the years, if you breed that white male with that white female you may get some super offspring.