User blog comment:MapiyaH/My goals in game for 2020/@comment-159.118.128.200-20200706164019/@comment-44638514-20200706174725

Yes horses can compete & train for Dressage while housed in the Grand Stable. Steeplechase is the only thing that horses can't compete in from the Grand Stable (I hope they fix that at some point!)

In your situation, it's a toss-up... On the one hand, T1 Mustangs level quickly, but on the other, *you* would actually get more diamonds from a more expensive horse type, since your screen time is limited per day (Mustangs shine if you can "harvest" them every 4 hrs). And you want to enjoy your game time! (At least I want to, lol!)