In ages past I was quite a leathercraft hobbyist, and used to make some molded leather soles for "Navajo/Apache" type moccasins. The leather I used was thick, but not as thick as brooks saddle leather, and there was a LOT more time spent on WOODcraft (making the "male" forms used to mold the water-soaked leather) than anything else. Also, the forms had a limited life cause I tack-nailed the wet leather to the wood and after a few uses you couldn't get the nails to hold anymore. I'm sure even the crudest Indian (East, not Native American) saddles use a more sophisticated (metal) molding system that's longer-lasting. Short answer: unless you're really attached to a particular saddle, AND really good at both wood-carving and leathercraft, it's just not going to pay off.