I have a bunch of foals who I'm triaining AD but they are assigned to an SD rider. Will this affect the speed of their training or does it only matter for shows?

-

Update: What counts as a good rarity for color breeders? Under 1000? 500? 100? I acidently bought a S/P/S stallion that is 1 in 261 and a S/P/P mare that is 1 in 59 and I'm wondering if that would be enough to interest people in breedings? Just wondering because I'm new and have heard it's better to work on showing first.

No, it does not affect any training or showing! SD riders will probably level up faster than the horse - so with higher leveled riders and more experienced riders the AD trained horses "might" even have a very very small advantage ;)