My guided tour says "we head out towards the Erg Chebbi dunes ... transferring to our camels we trek into the Sahara for a night at our Berber Camp ... and an amazing night out under the Saharan stars". I will be there last weekend in May. It is BYO sleeping bag! So what weight do you suggest please? I want to buy a *really* cheap one 'cause I will be leaving it there, along with a pair of bedsocks. I saw one today which says +2 to +7. Does that sound reasonable?