Proportions are relative by nature. Diferent populations differ greatly, there are astonishing contrast for example between Zulu''s long thin legs, and Mongols, with incredibly short legs for example.
But since there msy be not many Zulus (maybe more Mongols! no offense) here, it is important to highlight that also in the same population fenotypes vary a lot. And also almost allways short people have relatively, additionally, shorter legs, specially tibias. This is an advantage in terms of cosmetic proportions.
Wingspan is an ideal theoretical reference taken from the mistic mathematical "golden number", discovered by ancient Greeks and "revived" by famous people like Da Vinci. It really doesn't matter in real life except if lenghtening is exaggerated specially on femurs only. That's why mock up good computational simulations are the best judge. But they should be performed for more than the simple standing position. Some doctors have resources to do it or it can be "ordered" to graphical specialists. But generally only after final lenghtening people really "feel" the change. Again, if the amount of lengthening is reasonable, unknown people don't notice except the scars if those are not eliminated for example with laser.
So, to sum up, my opinion is that except if we do unreasonable lenghtening or depart from already extreme fenotypes, there's no great need to worry with proportions. The really remaining important issue is safety.
Proportions "works" by Mahoubian and Buldu are as good as others more used to diferent fenotypes.