It should not matter on the heli type to adjust the engine. The altitude and humidity will effect it some. Out of 3 OS 32's that I have owned they have all leaned out if opened less then one full turn. Have you checked to see if your low speed setting is too rich? When you are hovering does the heli start to loose power after a 2-5 minutes? Or does it hesitate when you advance the throttle to climb? It is always a good sign if alot of smoke is coming out since it lets you know the engine is getting cooled well, but 15% fuel usually does not have alot of smoke and runs not as rich as 30%. One way to minimize oil buildup is to use an exhaust deflector and try not to hover too close to the ground since the blade wash will dump oil all over the heli.