It just occured to me that if you are carrying a magnet in your PSK that is a stronger magnet than the compass needle and you are afraid that the compass will become miss-aligned magnetically because of that then all you need to do is to paint the south end of the larger magnet red and carry enough twine to suspend it. A compass is a magnet. If you are concerned that the stronger magnet will hurt the weaker one in the needle of the compass then you shouldn't be concerned that the weaker one will hurt the stronger one. Sooo. Hang the strongest magnet you have by a piece of cord around its balance point and watch which way it's south pole points - that's north. By carrying a magnet in your PSK you are actually carrying two compasses. No problem if all you want to do is determine north from south. If you use this trick to calibrate you more presice compass you can easily determine if it stills knows north from south and then use it to find your way degree by degree.