How do you guys mount?? The treeless give even 160 pounders problems mounting?? You are always using a mounting block or trying to find something in the bush??
Also if you get shifted to one side as in a spook the treeless is liable to slip.
Saddles are to spread weight. A normal western saddle has only an honest 60 square inches of area to support weight, the ortho flex I had had 300 square inches to support weight. You should not exceed 1 psi or pound per square inch for a horses back. You are sitting on your butt bones treeless so I feel sorry for the horse and the pressure points.
You couldn't give me a treeless.
I usually mount from a block or stump, no matter what kind of saddle I ride, treed or treeless, english or western. IMO, even light riders should not mount from the ground on a regular basis. It's bad for the horse's back over time, and you can stretch out the stirrup leathers.
I can mount from the ground if necessary. If no one is around to hold my off stirrup for me, then I use a lead rope to aid in mounting. I snap the lead rope to the rigging d-ring on the right side, run the rope down the cinch and between the horse's front legs, then up over the shoulder. Back on the left/mounting side, I hold the lead rope snug along with a big handful of mane in my left hand. The lead rope and mane help stabilize the off side of the saddle while I hop-hop-hop until I can get my butt up there, lol.
I use a horse chiropractor who is also a liscensed vet (she's no hack). She was very anti-treeless before meeting me. Once she saw how good my horses' back condition was, even with all of the miles we put on them, she was very impressed. I use specialized saddle pads and GOOD treeless saddles. I am also a "light" rider. I do not bounce at the sitting trot or canter. My horses backs are never sore after a ride, or the next day after a ride, and I do check religiously. My horses eagerly meet me at the gate, are happy/perky on their rides, and do not rush to get back to the barn.
You should not assume things.