It will definitely depend on how long (what kind of) the taper you want to get. I quess you'd hear the answer from some experienced cue makers in here. When it comes to my experience I'm just finishing my shaft to play with. On the previous turning the dowel 16,5mm at the tip and 21.6mm joint end conical shape weighted 6,7oz. After turning to 14,1mm at the tip and 21.5 mm joint end I've got the weight 5,3oz but my future shaft is 31,1" long. I'l have one more turning to get the final shape with 12,7mm at the tip and 14mm 12 inches after the tip. I want to get the shaft with more or less stiff hit and suspect to get the weight close to 4,9oz. So I suspect my shaft lose 0,4oz after the last turning. I'll know for sure after the job is done.