In reply to UKC Articles:
Everyone is different but climb high, sleep low followed by climb high, sleep high(ish) seems to work well for me. The only trouble with doing high up day hits is that if it's something that's dependent on a lift descent, you have to make sure you get the last lift down or you're in for a very unpleasant night, even if it's in a hut. I've missed the Midi lift a few times on a first day out at altitude and had a lousy night in the Cosmiques. A brutal way to acclimatise! However it works well if you get back down the same day.