Where do you see creosote build up? In the firebox? I've always had it so I don't know any different if so. Not sure what size my pipe is, Richard made it. The glass I have a small piece of wood holding the glass away from the door slightly which keeps the glass from clouding up with residue which it used to do when it was tight against the door.
I always figured that little bit of air constantly finding it’s way into the lower burn chamber went right up the refractory into the main firebox and lets it smolder longer after it shuts down.
I did have the one prototype I made, used the vacuum built in the stove from the draft fan, draft pulled it away from the front plate of the viewport and let the air wash work, very light duty springs pushed the glass back against the plate to shut the air off, less creosote definitely up top and it worked reasonably well except for two annoying problems.
1: Certain weather conditions would let water in and then it would freeze if no call for heat for several hours, once the stove was actually burning the heat would melt the ice and it would open, but not before completely crudding up the glass.
2: With no air wash between burns, the glass would quickly get dirty as some fumes linger in the bottom of the stove after it reaches temp and shuts off. I mean in the course of over night it would be completely covered and would require cleaning everyday.
I was using basically the equivalent of pyrex, no matter how filthy or baked on the glass is, always cleans right up, just was annoying to do so.