About the fit: I had to thread the back straps through the loop just enough to stick some of the soft Velcro through to keep my heel from constantly rubbing against the rib along my back. Because the front strap loop is on the small side, you actually move a little more to lift the sandal in the front, which puts more stress on your entire foot. On the subject of sweat, after walking in them for about ten minutes, I noticed that they squeaked. It took me a while to figure out that this sound was caused by sweat as my feet were being pressed through the texture of the sole your feet are resting on. If you zoom in on the image you will notice that something has formed in the grooves. It's dust and sweat off my feet after a month of accumulation.