Just put in a 1402 insert and I am having trouble trying to keep the glass clean. Get's heavy black on the sides, the middle stays fairly OK. I have a good draft, no smoke spilling back into the room. Any suggestions? Also, anyone who has a 1402 and wants to give me some pointers would be appreciated. Burn temps? Location of thermometer? Grate or no grate? How much wood do you load and what size at what temp?