Bulldog,
These are the exact questions that I have been pondering. So I am delighted to respond. I loved the trip, and did not find it overtaxing, but there were a few challenges, and at one point, when I was underdosing Diamox, I do think I veered into AMS territory (despite the good acclimatization route), and thought I might have to quit. A few points.
1. While I was not the fittest person in the group, I had by far the easiest time on the mountain, and also the most fun. I believe this is because I was the only person who hiked weekly (and backpacked) in the 8-10 weeks before the trip. The others relied heavily on the gym, stair climbing, biking, and other activities to train. Different muscles, different rhythm than hiking, etc. They were adapting to a type of activity that I do all the time. (I found Mission Peak, in Fremont, to be a terrific winter training hike for Kili.)
2. The other reason I think I had the most fun is because, although my mountaineering experience is limited, I have picked up some skills that helped me conserve energy. I used a rest step extensively on summit day, and I also did some pressure breathing here and there. I showed others the techniques, but people feel silly I guess, so only 1 or 2 folks took me up on these suggestions. Be that as it may, at the end of summit day, I was still full of energy, while everyone else crashed in their tents. (While Kili is strenuous, in my opinion, climbing Shasta from Helen Lake to the Thumb is even more so.)
3. Yes, there WAS a moment where I thought I might not be able to summit. It occurred the day before the summit day, when I was hiking from Barafu to Crossover Camp (i.e., 16,000'). This is a short hike that only gains about 800-1000 feet, and is done in perhaps an hour. I had skipped the morning dose of Diamox (in the Eastern Sierras, I only take 62.5 mg once a day, before dinner), reasoning that Diamox does its best work at night. I felt fine so long as we were moving (probably because I was breathing at an elevated rate due to exertion). However, whenever we stopped, a headache would start. Before the lunch break at Barafu, the headache was manageable -- I would pressure breathe, and just walk around. After the lunch break though, we did a climb that had some scramble to it, and each time we would pause, I would get a horrible pulsing headache. I could not stop visualizing what was going on in my brain, and the potential for HACE -- just felt like something in there would explode. It was scary. So when we got to camp, instead of resting, I spent an hour walking around the camp. Nonetheless, that night, my 02 blood saturation was the lowest in the group (74 percent), and my heartrate was elevated (105 or so). After talking with the head guide, I upped my Diamox to 62.5 mg every six hours through the summit. I did not experience another headache, not a mild one, not a severe one, none. Following the summit, my 02 blood saturation was 91 percent, and my resting heart rate had gone down to 62. Sure, some of that was the process of coming down from 19,300 feet. But still. Diamox did its job, IMHO.
4. I had no appetite problems on summit day ... just the opposite, no doubt because by that point, I really was properly acclimatized. I felt great. Before we reached the summit, we stopped for lunch just under 19,000 feet. I scarfed down, with no problem, a large lunch of corned beef, cheese, a roll, a vegetable filled pastry, cookies, and fruit. No nausea. No appetite issues.
An odd thing to me is that only two of us brought electrolytes. They saved me early in the trip when I was battling dehydration due to a bad reaction to their water treatment chemicals (for the rest of the trip, I ended up treating my own water with a Steripen that I brought). I then ended up handing out my electrolytes like candy to others as various issues arose in the group and were then addressed. I think that the outfitters would do well to (1) supply electrolytes, an (2) encourage folks to bring them.
I anticipate that my future Diamox dosing will be as follows.
Sleeping altitude less than 13,000 feet: 62.5 mg/once a day, before sleeping.
Sleeping altitude higher than 13,000 feet: 62.5 mg/twice a day, to be adjusted if necessary.
