The SIG fuel (20% 50/50 oil) should provide protection from a lean run.

If it putting out smoke when you advance it, it is rich (or has been idling for awhile). Lean your idle screw. Do this in 1/8 turn increments, WITH THE ENGINE SHUT OFF, and restart and try the transition again. Do this until it transitions smoothly. You MAY have to redo the high speed needle again (if you do, recheck the transition and adjust if needed - the idle will only require a tiny adjustment, if any).