ClipperDelta, thanks for the thorough response. I will plan on booking on either Tuesday 10 Oct or Wed 11 Oct and not expect Z availability at time of booking. If I do need to fly later, would a Saturday departure (14 Oct) have better chances than Thu, Fri, Sun, or Mon?
For MCO - NRT, I am showing one way B fares of $1941.00 (including tax) and round trip M fares of $1725.04. Am I going to face some penalty from DL (I have 400,000 skymiles that I don't want to lose) if I just buy the M and toss the return?
Again, thanks,
Marc