Unfortunately GIN (standing for Young Italian Naturists) seems no more active. Many members are growing up and seems hard to find new members.
Anyway I would like to give you an overview of contacts and references on Italy:
The Federation do mainly a burocratic job. In Italy there are many associations that support INF-FNI members and naturists based on their geographical location.
Italians are not known for their language capabilities. So,please, if you will contact them, expect to wait a while before someone could be able to reply :(
I and my partner are into this world from only 5 yrs but We can offer our support to anyone would like to have information about Italy and Naturism in Italy.
At least we could try! :-D