I need some advice here. I need to book a cruise, and want to do it through United Cruises, because it will earn me 30000 RDMs 6-8 weeks after the cruise completes (late summer 2012). I don't know which MP number to give.

If I give my current MP number, it will no longer be my MP number when the cruise completes. I fear that the miles may not post then due to invalid MP number.

If I give my current OP number, which will be my future MP number, I fear it may not validate now or be treated as a OnePass Cruises booking, which gives fewer miles (10000 for the very same cruise).

I would like to give the FF number that maximizes my chances of getting the 30000 posted in late summer without hassle. Any ideas which might be less problematic?