Redundancy has its place ...but I feel for you when you're already looking at a heavy load.
BUT ..with that said ...its hard for me to give up the backup capacity.
And tossing your PSK into the pack with everything else ...brings up one facet of the personal PSK concept that I try to consider ...and that is not having all my eggs in one basket.
I would try to minimize my PSK and package it in such a way that it could be on my person at all times ... in a cargo pocket or on my belt, etc. The idea being you always have when you take off your pack. MOre than one survival story has started with a trek away from camp to get water slip and fall slide down a hill blah, blah blah.
Your BEST survival tools are the one you have on you. Obviously you can't have everything on you all the time ... BUT a minimalistic few key items can make a dire emergent situation much more tolerable and thus potentially survivable.