Field sharpeners

[khameleonx1]

I am looking for a recommendation on a small portable field sharpener. Something that would fit in a small tin, or strapped to a sheath. I was considering something like the Smiths pocket pal, and it looks like benchmade makes a few nice small ones as well. The disadvantage to these I can see is most appear to be standardized to 60 degree's. If a stone is suggested, how does one 'properly' sharpen the knife, given the stone is obviously small, would more of a circular pattern be used in this scenario?

thank you.