Unfortunately, it is not possible to try them before to buy .... So my choice, based on discussion and impressions on shapes, is the QF.

Thank you all for your answers, i Will inform you after first impressions

in fact I have a second board for the windy conditions or bigger waves. It is the reason that i was interested by the quadrafive. For the moment? I don't know which i will get it but he hellfire seems to be very interesting ... which one is the most funniest in the conditions described in the beginning of this post ?

Thank you Felix for your quick answer.
What are the differences between these two board ? and what are the advantages of the quadrafive in comparaison to the hellfire ?
Many thanks