Just quickly Dot, the owners I've referred to are breeders as well as buyers. They've bought when they've encountered the pitfalls in breeding you've mentioned, (or have bought to add to the team of homebreds) hence the thought bonuses should go to them. They're not sellers, of yearlings.
Would like to have more time right now to give thought to what you've written but for now, touching on the foals that don't change ownership. What would a race series that excludes sales horses do?