In reply to steveej:
I would advise against that. Doesn't seem enough time to adequately acclimatise, certainly not in my experience. I'd say I'm a bit slower to acclimatise than most mountaineers though.
Everyone acclimatises at different rates so it might just be possible for some people, but I think it's pretty optimistic. Also it leaves absolutely no room for sitting out bad weather, which you have to factor in or your chances of getting a window for a summit attempt are very low.
The maths do not 'stack up'. If Denali at 6200m = 3 weeks then Shisha at 8000m+ does not = 4 weeks. The higher you get the slower you acclimatise so it will take more than 1 week extra to get acclimatised to the extra 2000m.
Post edited at 23:49