Like John Doe I made my stance wider this year and had to mess around with my angles. I too was getting knee pain with the wider stance. I messed with my angles and I was able to make the pain go away.
To your bindings I have set up a lot of Flows. Some of the ratchets on the older bindings would actually tighten during your riding. This may have been an issue in your other bindings. Remember they don't need to be as tight as conventional bindings. I love the new stye with the "kick-up" of the strap.
Hope you get it dialed in again and start to ride pain free.
I often ride with riders below my ability and they don't slow me down. I enjoy riding and chatting with them and just being with friends old and new. So meet up with as many forum members as you can. Great friendships can be formed.
-I'm Slyder and I suffer from "Gummer Syndrome"