There are a couple of threads discussing the pros and cons of adding rubber to leather soled shoes, but none of them really do a great job of discussing the various options for doing it. I am going to do this to 6-8 pairs (not sure about two of them), but I want to make sure I maximize the benefits while minimizing the costs. What I'm curious about is: What type of rubber should I have put on? How much of the sole should I cover? How thick should the rubber be? I'm thinking is simply covering the ball tread (?) of the outsole. I might see about having the rubber split into 2/3 sections to allow for greater breathability, also leaving a quarter centimeter or so between rubber and the edge of the sole). Thoughts?