Thank you very much jgf for your comments about the F111.
The 8,11 is a great board for sure and the more I think about it the more I think that I will keep it for a while. For me it was fantastic from 5,5 to 6,5 when I was 110 Kg, but as you said, it can't handle bigger sails.
As far as I'm concerned I'll loose some weight before buying a new board. Then when I'm back to 110 kg I'll buy the F111 (for 6,5/7,5) or maybe the F122 (6,5 to 8,5) and keep the Naish for 4,5 to 6,5.
I think that the 101 is definitely to small for me