I have a couple of friends that will ride the CA in the middle of Feb.
I recomend to use MTB wheels, from Chaiten to Coyaique you can find a couple of asphalt roads (thats the door of the CA), but no more than that.
In this season expect anything from the chilean south, need to be prepared (from sunny days to snow). I just came back from cyclo touring Osorno-Bariloche, and I had lots of sunny days, rainy and snowy ones.
I'll ask a friend from Coyaique if it's crazy to ride the CA in march.
Cheers.