Being a slender guy (6foot and 165 pounds) and having a short-ish torso for my height (I wear a 38R jacket, which should fit a guy 2-4 inches shorter than me, on average), I have a hard time with tie length. Most ties are just plain too long for me. I aim for the top of the kilt/top of the buckle area, but this doesn't always work out. If I'm wearing a waistcoat I'll just tuck the tie in some place and be done with it. If I'm not wearing a waistcoat, I'll adjust the tie so that the wide part that everyone can see is the right length, and then tuck the "tail" into my shirt, much the way Jack Daw does with his tie when piping. Or sometimes I'll just follow his example outright and tuck the whole darn thing into my shirt.

Wow, that was a rather lenghty post that really boils down to, "I do the best I can with what I have."