I wanted to suggest you find a saddle to borrow that has the stirrups set where you're thinking you want them and go out for a 3 hour ride and make *sure* they're comfortable for you. My mom bought a bob marshall treeless endurance saddle, with the stirrups set farther back than the usual sport saddle. I usually ride english, but happened by her campsite and took her horse out with that saddle. I had to ride with no stirrups because the position of the stirrups hurt my knees so badly. Turns out they hurt hers too, she sold it (at a loss) after less than a dozen rides in it. I'd never get one with stirrups positioned like that again, but there's got to be a happy medium out there somewhere!