My $.02
CT225, 40 hours. Starting in low teens (10-15 F), I just use the glow plugs for about ten seconds and get very little smoke. If I don't use the GPs long enough, or if my throttle is set down to idle, it will smoke a lot more. I (usually) set the throttle about 1500 RPM before I shut it down when I park. Helps to have it there when I start next time.
-rus-