From the World Flying Disc Federation page
Number of attempts for distance, MTA and TRC should be limited to no more than three sets of five on any one day. If there is doubt about the rules, it is recommended that the strictest interpretation be adopted. For any attempt, expert officiating by impartial witnesses is required.
The throw must be made over level ground. No noticeable degree of slope is acceptable. There is no restriction on wind level for the outdoor record
. Measure to the nearest centimeter.
For roller distance attempts, the throw must roll on the ground for at least half of the total distance covered.
For upside-down distance attempts, the disc must be released with the top surface or crown of the disc facing the ground. It mus also travel the entire flight in that manner, including landing upside-down."