One thing that I have found useful when it comes to offering a stock shape that best fits a person, is to have kept track of many different styles of rifles' particular dimensions...drop at heel, toe, length of pull, height above the top flat of the sights, distance of rear sight to the breech, and so forth. Also, I make a comment about the rifle's suitability for offhand shooting, and record the info for later study. What you see eventually, is a pattern.
Also of remark, is the many different ways that shooters shoulder a rifle or a fowler, and this too can make a great difference in what will or will not fit them, if they continue to shoot that way. I try to encourage shooters to bring the gun to their eye rather than shoulder it and bring their head down to the gun. With the first method, a length of pull can be much shorter than with the second, though it is often difficult to get people to change. In trying to capture the essence of the longrifle, one should try to stick to dimensions and architecture of the old guns. Rifles with 14 1/2" - 15" lop's lose it, to my mind.
There is no reason a Lehigh rifle has to be a cheek buster or require sights that are absurdly high off the barrel, if these elements are adhered to.