I agree that it sounds like you just too rich on the low end.

Also, no matter what you do, short of an on-board glow lighter that kicks in at low throttle, you will never get an inverted glow 2-stroke engine to idle as low as an upright one.

Try a hotter glow plug, maybe even a 4-stroke plug. Those plugs will stay hotter longer, reducing the ability of the fuel to put the plug out. Many years ago, I used the Fox Miracle plugs for some engines. It's a pretty hot plug.

An idle bar, as suggested above can't hurt either.