Never had carb icing in around 1500 hours behind Rotax 912 and 912S engines. And have not even had a carb heat system in last few hundred hours. However, the air filters have always been at he back of the cowled engine compartment so the intake air gets quite warm quite quickly.
In the Tecnam, is cold air ducted in from outside? If so, think you will need an effective carb heat system.