When I have trouble creating a hook, I first create a regular connection where I want the hook to be placed. I create the new CP on the target spline with the “y” key. The idea is not to deform this spline too much. This will temporarily break the target patch since it now has five points. Connect the dead-end spline to this new CP. Select the new CP. Hit the tab key until the green “handle” shows along the target spline. Hit delete. This should delete the CP on the target patch, but leave the CP on the end of the dead-end spline. That CP is now very close to the target spline. Now without moving the CP, I create a hook, using the right mouse button or the “~” key. It is slower but this almost always works for me.