I would use a conformal fanny pack rather than arm holsters personally. I have quite a good one made by Patagonia. It's designed for runners/joggers. Trade the SAK Farmer for one of the one hand opening models. Assume that any mishap is going to result in injury's that deprive you of the use of one hand/arm. Trying to open a SAK knife with one hand is difficult at the best of times.
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I don't do dumb & helpless.