Hi everybody again,
you won't believe that, on the subject, I got another point of view from my windsurfing equipment dealer in Rimini (I must admit that he's quite always right..) .
According to him, the JP volume is actually less than 120 liters, so that board can stand the 30 knots under my heavy weight. The problem is that the Core is a kind of "soft" sail (designed on the Pryde "Wavepro" flexible mast - the one with red graphics) - and it doesn't work well with the hard (as it was not "tapered") Pride wave carbon 45% (model year 2000). That's why he suggests to rig it on a new Pride X6 RDM 400 "and you'll see it how it works . ."
What can I say ? Perhaps the above solution is the safer one: if the rig doesn't work ..I will give the mast back !!
I thank you all very much for your support ! I wish you a windy 2010 !