A 66 result is ideally made up on the spot. Also, this should have been placed in the RMSS/FRP section, as the UM66 and UM100 special static maneuver results were a RMSS addition.
Since an unusual result can and should make use of the situation in which it is rolled, I would not prepare them in advance. On a herding roll, a giant eagle could swoop down and carry off one of your sheep, or a sheep could fall into a sinkhole, leading to the discovery of a long-buried ruined city, or one of your animals could eat that herb you had on your belt, or they could terrify the child of a VIP who is playing nearby.