I prefer the method that your nose should be 1& 1/2=2" back from your thumb when grasping the neck of the stock in a shooting position.You adjust your scope to accomodate you,not the opposite.
That is the method I use - tip of the nose to base joint of the thumb. I guess however that it might give rise to some odd results if you are one of those people who drops their head forward to the comb, looking out under your eyebrows, rather than keeping it proudly upright and bringing the comb to it.
I should also say that I'd rather have a stock a mite short than too long. A stock too long tends to snag or at least slow me down when I mount the rifle or gun to the shoulder. I am a bit over 6' tall, but have long arms and a long neck, so factory stocks are all a bit short really, and I have happily shot with rifles like SMLEs, which have quite short LOP. I've even shot with the rifle I shortened for the kids, which has a 12" LOP. As long as there's nothing going to hit my face or eyebrow, and in the cased of scoped rifles as long as the scope can be put in a position where I'll have enough clearance and a full FOV, I'm not particularly bothered.
I think it is much more critical on a shotgun than a rifle though, and there I'm a bit more inclined to make adjustments.
