A Crates Lady Reiner. The regular Reiners are nice too, but the Lady Reiner has a narrower twist. You can get them in a round skirt as well if you want it a little lighter or your horse has a short back.
A lot of the older Herefords had the narrow twist, sure made for a nice day long ride! Or even better, the week or more long Trail Rides, doing 20+ miles a day!! I never got sore in that saddle, could have been partly the old mare's smooth gaits too. There are quite a few available, for lesser amounts of money. I love my old Hereford saddle, just doesn't fit the horses I ride now, DARN IT.
Where do you like your legs to hang? I don't think reiners are that comfortable for spending hours in the trail, and if you prefer your legs to hang straighter underneath yourself, you probably won't like a reiner.
I would look for a ranch cutter. They often have narrower twists, fit well on high withered horses, and are built for spending long days in the saddle. The ones I've seen have hard seats which can look uncomfortable, but IME, hard seats are much more comfortable on long rides.