@Anna Sleds can be used only till 14.200′ Camp. The Headwall is too steep for a sled and the ridge afterwards is also not suited for a sled. So there is no point in taking the sleds beyond camp 3. Depending on the conditions your backpack may also be very heavy when going around windy corner as the slope there is sideways to the path and a heavy sled that is moving from behind you to below you can throw you off balance. Thus most people try to carry more stuff on their backpack that day. Other than those occations i would try to pack up to 2/3 of the weight on the sled. But in any case keep the center of mass from the sled very low to avoid that the sled rolls over all the time.