If you ask 1,000 people you will get 1,000 different opinions and ways of doing things. Personally, I use a method as old as the world, and that has proven itself at a time when we didn't know all these chemicals for leather.
Once I have sanded my slices with 500 paper on a wooden wedge, and after burnishing wet,I apply tragacante gum, and sand again with 500 paper when dry,, then I apply the gum again and sand with 1000 paper, then I apply my beeswax/carnuba wax and polish and do this as long as it doesn't shine like a mirror.