I didn't see any questions answered,...
I didn't see any questions answered, previously. BUT I still hope somebody is listening, for I ask if the 65 has a larger (longer) hip belt? Than the 50? Because the 50's belt is pretty short in length; barely catches hip bone!
late answer; but, I am fairly certain that the 65 and 50 use the same belt. The overall dimensions are hardly different; but, an extra inch in height and width amount to a considerable amount of total volume.