Paul,
Everyone has their own idea of how the smoke tube should be installed. My personal experience is with the tube bent so that the exit is 1.5 - 2" behind the nozzle and the tube exit well into the nozzle stream pointing at center. If it's too far out from center, the exhaust from the turbine tends to blow a lot of the oil away before it's burnt into smoke. You need to experiment with your own installation a bit for the best results. Also recommend the mix is set up so the smoke comes on at about 1/3 throttle minimum and increases from there.
PaulD