two ways to make 2 stroke oil smoke less:

1. Decrease ash content (most synthetics are very low in ash content and some of the higher quality 2 strokes such as Pennzoil are also low in ash)

2. Increaes the oil flash point to decrease amount of oil that actually burns.

I personally use a mixture of oil that is 80% synthetic and 20% castor oil. THe synthetic has low ash and the castor has a very high flashpoint and doesn't burn much. Result is less smoke but more liquid being spit out the exhaust which actually is a good thing because it did its job in lubricating the engine the entire time in liquid form.