The key is experimentation here. Start with a flight that appears to work and experiment with similar shapes to perfect your throw. Always remember the shaft/flight combination that works with one barrel may not always work with a different (shorter or longer) barrel. You may have to adjust shaft length and flight size accordingly. Again, if you want a faster, straighter dart, use a smaller flight. If you want your trajectory to arc and to slow your dart go up in flight size. Note: Your shaft length can also affect this trajectory.