Someone on here once argues blind to me that if i wasnt using a 110mm (middle of the range) length stem then my bike didnt fit me properly. Utter BS! there are a lot of these rules of thumb around and they are fine so long as you realise thats what they are. Not hard fast rules. Dont be surprised if none of them work and dont pay a fitter to get his laser out and set you to them to the mm. What feels right, is right. And what feels right will change with time.