I used the "one knee" stance when I first started out. As I moved up and started doing higher level games, I switched to the box stance. My reason was simply self preservation. Too many bruised thighs to continue the 1-knee.
As for glasses, I use them when needed.
Sunny, clear sky days. One tip I would offer is, if you're wearing them and you need to discuss something with a manager, remove them for the conversation.