Yup, quite the zombie thread. 5 years old, and OP last post was in 2016. But still timely advice for new people checking into the sport.
The reason that synthetic is used for distance sports is because leather take such an awful beating on the trail. There is just so much hard usage, so much sweat, so much accumulated grime collected over the miles that having to clean leather all the time just exhausts the stitching, the natural material and shortens its lifespan. I started endurance using all of my beautiful leather foxhunting tack, and soon found out why the experienced endurance riders had hung up their leather and switched to synthetic. My leather tack is now only used for very special occasions, and all of my daily riding is done using my synthetic beta tack. Even my stirrup “leathers” are actually synthetic with hooks rather than buckles.
I don’t use a rubber girth for my newest endurance horse - she can only tolerate soft fabric dressage girths that are covered in sheepskin. She is so sensitive that even covered in sheepskin my rubber girths will gall her. So the rubber girths remain in the tack room, and I only use soft fabric girths on her with elastic ends.
