In our published altitude paper, interviewing 1800 attemptees, we found an advantage if someone had been to 10,000 feet within the previous month.
there is no doubt that there is a loss of acclimatization with time, but it is not clearly worked out.
It may be quite different at extreme altitudes (>18,000 ft), than it is at 12-14K. I don't think it's well known.
It IS well established that altitude at which you sleep has more effect than simply day activities.
Sound like you have a good plan, G'luck!
