I'll be doing some mountaineering courses in NZ presently, and will need a suitable pack. Requirements (in no particular order) are; 55-65 ltr capacity extendable lid compression straps lashing points for ice axe, ice hammer, and crampons. plus low weight, durability, reasonable cost etc. etc. Used or new will do, not fussed either way. Rather than wade through hundreds of designs from dozens of mfrs., has anyone got any (sensible) suggestions?