Thanks Roger for very detailed answer!
I'll try to learn that by heart and give my husband a very sophisticated answer later this evening :-)
Where do we live... In a windsurfer's paradise where even the sea is frozen at the moment and it will take until May the lake we go is free from ice.
I liked that "do all you can to get a 100% carbon mast" :-) I'll try to come up with something. I guess I'll buy that Rio S Sport anyway and when the time and especially the weather is right, I'll try our GO again. I know the technique in paper but I should have time to try that on water and then come back and ask the right questions.
But thanks again! This was very helpful!