try to use NWA award search past 351/352 days in advance and you will
get a notice about too many days in advance.

of course (barring platinum status) that typically means 352 for your Return flight, which complicate things.

by playing around with the # of passengers you can get a sense of how
many seats are available (ie you'll be pushed to rule buster status when your
# pax exceeds number of seats)

I used DL sky miles to book NWA awards and thats why i know about delta having a shorter lead time. the made a "one time exception" and held those seats until they were available to delta. this was critical as we needed to have four seats and we already had 3 booked with nwa using WP miles

that being said we ended up getting two seats on a tuesday night, and two more on the next flight (approx 50 minutes) that was DTW-AMS june 2006.
there were ONLY two WP seats on each of these flights (at least at that time
available to Silver elite)

with an open jaw we got 4 seats from Paris to London (6:00 pm friday, air france) and finally 4 seats from LGW to DTW on July 4th.

we got all four tix at 50K each.

additionaly, i found i could not "trust" the award calendar - sometime seats were available when the color coding indicated they were not.

brad