this next flight will probably be the final test flight (assuming all goes well) before they attempt to go for the Prize. The article states that SpaceShipOne will only carry one person and won't be ballasted to make up for the other two seats, so this one won't count. Because it'll be lighter, it should go quite a bit higher than 100 kilometers.

Knowing Burt's reputation as I do, it wouldn't surprise me if they do a glide test with the ballast before going for the X Prize runs, just to make sure everything behaves as it should during the glide and landing. They can configure the White Knight to replicate SpaceShipOne's flight characteristics (note how both have the exact same window placement and almost identical avionics), but I don't know if that will be good enough for the heavier landing weight and possible changes in the center of gravity. Burt has over 3 decades of flight test experience. He didn't make it this far by being less than thorough.