After six, 12 minute aerobatic flights, I would have a thin mist on the belly and tail surfaces. All that is needed to clean my plane is a 1/2 sheet of paper towel. This, flying my Yellow Aircraft 120 size Extra 300L with the 160fx on glow with a Jtec dual snuffler and Hobbico extensions. The same goes for my 1.60 GP Gene Soucy with a Bisson ST 4500 muffler with one exhaust closed and Hobbico extension on my other 160fx. It's a matter of getting the exhaust away from the plane. If I was running a tuned pipe, oil would not be an issue.

Large glow engines get rid of the oil and are not slimers like .40 size slimers.

I still like the idea of flying gas with this engine and would accept the slight drop in performance.

How is your fuel consumption on gas? Have you timed a run at full throttle with a tank of known size? On an APC 18X6 @ 9200 rpm with 5% nitro 20% oil glow fuel I was getting 5 minutes 20 seconds on a test stand and 8 oz tank.