Bring the theodolite!
Many years ago, before GPS days, a group of friends and I had the occasion to try to determine which was the high point among a group of "bumps" on a fairly flat topped hill. Of course not owning an actual theodolite (or even a laser level at that point) we had to improvise. We brought a 4 foot aluminum carpenters level. It was actually very effective, when braced on a rock or branch, with one person looking at the bubble, and another person sighting along the edge of the level. I would wager that we were able to determine "higher or lower" elevation at a range of 100 yards with an accuracy of a couple feet. This is cheap to do. You could certainly try this on the Tripyramids.