Women's fingers tend to be appreciably thinner, yes, given that this is infantry lore it's safe to say that it's calibrated to men in fighting trim (which impli

Women's fingers tend to be appreciably thinner, yes, given that this is infantry lore it's safe to say that it's calibrated to men in fighting trim (which implies no extra fat on the fingers). There's still some variation but (the only reason I'm commenting) larger hands tend to be on longer arms, so this normalizes well enough for a rule of thumb. Last point is that with a rangefinder one can calibrate this to one's own body, which is, after all, what gets used as a metric.