With length I think it's generally personal preference but in this case, I went with the 156 because of the waist width. At a size 10 Burton driver X, the footprint gave me about a quarter inch of toe and heel hang, which is about where I like our personally. Also, I will say that despite the effective edge comment above, I felt that for carving ability this board rode like a 58 or 59, which is the length I typically have ridden in the past. I spun a couple of 3s and 5s and it felt pretty light but I think the diodes had something to do with that... But again so much of this is personal preference so others might think differently.