I forgot to add something from my previous post. You have 90 days to complete the challenge. Becaue the tickets are going to be used in mid-October and late-December, I don't know if the 90 days will expire before you finish. The 90 days begin on the date you asked to start (either the first or 16th of the month) and ends 90 days from them.

To ensure that the Challenge will not expire, I suggest that you ask for the challenge to begin on December 1, 2005. The second ticket alone (with booking in the Y class) will get you the required 10,000 points. This way you do not run the risk of the challenge ending a few days before the end of your travel.

Hope this helps!