Responses to altitude are so individual that it's really hard to tell until you try! You probably won't find out until your 14 mile day to 11,000 feet.

If you really want to be sure, insert a day with sleeping at about 9,500-10,000 feet in between the easy day at 8500 and the hard day at 11,000. The best would be to split that hard day in two, if you can camp somewhere near the midpoint. You may have to do that anyway if the altitude/long day affect you.

Also, keep well hydrated and plan a high-carbohydrate diet.

Lots of great information on altitude sickness and acclimatization from the NOLS Wilderness Medicine Institute here.
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May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey