After almost 1 year of continuous burning here the report on the Window in the Alaska:
There is some etching of the ceramic visible now, last week when I had the stove shut down I scrubbed the window and tried to get all the impurities off. there is a slight hazy coating on the surface, very difficult to remove. I did use coarse rouge and a cloth wheel, got it mostly clean. I recoated it with Butcher's. There are some hazy spots and etching, but it's mostly clear and still easy to clean. No perfectly clear like the hand fired, but I can see the ladies.
I wonder if anyone has tried to use a product called Rain-X for this purpose.
Rain-X is silicone and alcohol, you can try it but I wouldn't apply it when the stove is burning.