I ride, preferably in a dressage saddle, but always with a classical seat, which immensely lengthens the leg. In a dressage saddle, I sit with a longer leg and stirrup than I would a western saddle. I 'might' shorten my stirrup when jumping, depends how good my balance is on a given day.
Proper riding is proper riding, no matter the discipline. My instructor taught me to keep the same seat no matter what saddle I ride in, and my butt has touched Aussie, Western(s), Saddleseat, Dressage, Jumping, and All Around saddles. Watch some of those jumping saddles though, they push you forward into a jumping two point.
And I would ask around some of the western barns. You might find an English rider among them. My instructor teaches mainly hunter jumper because that is what is popular in my area, but she can school people in any of the western disciplines.