I have used my points three times for airline tickets. Twice when the fares were lower (30,000 points) and one times recently. It does not matter the cost of the ticket, you still have to use all 50,000 points. You can specify which flight you want to use, so I specified non stop and the specific flight. It is very easy to do.
By the way, I am from St. Louis, and if you fly from the airport in Mascouta, Ill, using Regent Airlines, the flights are very inexpensive, as opposed to flying out of Lambert.