15.2 - 15.3 is ideal for me.
Tall enough and easy to do everything. Don't need a stirrup, a strong push up and hard pull to get into the saddle. Can almost jump into the saddle.
So of course I didn't end up with that. My older, little horse has hopefully topped out at 16.1 and the youngester is 16.3 on her way to 17+. Couldn't find a way to stunt the upward growth
Still looking for a saddle with a rope latter attachment for when I start training the younger one under saddle later this year. I keep hoping she'll stop getting taller.