Altitude acclimatization does NOT occur in the hours you are hiking up the mountain!! For people who have altitude issues, spending two nights at 8,000 to 10,000 elevation is what helps. If you haven't done that, then it's pretty much a crap shoot on your hike, and you just go up and then see who is affected and who isn't.
You should hike at whatever is a comfortable pace for everyone. That is why keeping it steady (not fast!) up to Trail Camp is a particularly good idea. Anyone with energy to spare and not affected too much by the altitude can go hard the last half, or even better the last quarter -- from Trail Crest to the summit.
