I believe this rock outcrop at the western summit to be the highpoint. My GPS showed this to be 5-6ft higher than the middle summit, and 15-17ft higher than the eastern summit. There is a register located here as well that seems to indicate similarly. The topo shows a spot elevation of 8,417ft for a point west of this benchmark which may lead one to believe the western summit is lower.
I think the evidence is only clear in that the eastern summit is lowest. The western and middle are perhaps too close to tell. You mention in the main text that the western points are 'obviously' lower which I think is misleading. To help other highpointers, they should be encouraged to visit both locations.
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