Stance is really personal, it's not like anyone can tell you exactly what angles and widths are best. Not only do people have different preferences, they also are built slightly differently physically so what's comfortable for me isn't always comfortable for you. Just play around and change your stance up slightly until you find what you like. I personally go with 18 in the front, -9 or so in the back. If you ride switch a lot you might want a negative angle on your back binding.