Don't forget each line carries other Lipizzan stallion lines as well. The breeding stock is simply too small to maintain distinct lines. I'm sure your Siglavy also has Maestoso, Conversano, or any of the other lines in his 6 generation pedigree. I live in New Zealand and want to put my mare to a Lipizzan, by AI if possible. Check with your veterinarian first, because in almost all cases, your mare will need to be ultrasounded every 12 hours to determine the best time to inseminate frozen semen.
Timing is more critical than with cooled shipped semen.
I think very few don't graduate because they are carefully chosen for the school. Some are eliminated because they get too big to match the other horses in the school. They are sold to or go back to Piber for breeding services. Andalusian horses are, of course, Spanish horses. I suppose you could say the Andalusians are the ancestors of the Lipizzans.