Neo-ceramic is the right material. Glass installers may have some scrap, i have a stack of 2 and 3 inch circles of this material.
The air curtain works well but not nearly as well as heat, high heat is what keeps a
wood fired heating system clean, that and we do not damper the fire down...ever. the resulting smoke and poor efficiencies plus deposits that form in this condition that will never soot up glass in our stoves.
A friend of ours has beautiful, clear glass, and runs damped full time, he uses a liquid solvent. He says it wipes clean easily.
Somebody used abrasive on our window and it will never be perfect again. People do the darnedest things when they just gotta have it a certain way. Do not use abrasive in a quest for that crystal clear image you picture of the inside of a blazing soot factory!