That's not carb icing. You'll usually find the carbs ice after a little while when riding, especially on frosty mornings. It happens due to "latent heat of evapouration (or vapourisation)". Oh! Get me!
Thats a technical way of saying that as the liquid fuel vapourises in the carbs, it draws heat in from the environment which cools the surrounding metal, leading to icing.
Curvy carbs have heaters in them to prevent this happening but they can be overwhelmed as has been mentioned on the forum.
The stutter you have on start up is just the bike coming on song. A squirt of WD40 on all of the wiring, should work wonders along with making sure your carbs are balanced, plugs are good, your choke cable isn't sticking and all the other usual winter checks. For the first couple of seconds its just sorting itself out and getting warmed up. If it gets worse, it might be worth clearing the pilot jets out in the carbs too. But again, as long as its not longer than a couple of seconds, I wouldn't worry.
C