3D sky plots for NGC 1261 (top) and NGC 1904 (bottom). The position of each GC is shown as a red star and the particles from the N-body simulations are shown in blue throughout the paper. The insets show the distribution of particles close to the clusters and the outlines of the fields targeted by S⁵ (black circles). We also plot in purple the integrated orbit of each GC given the gravitational potential described in Sect. 3.1, and the direction of motion of the cluster is indicated by the red arrow.