A full diagrammatic and spatial test: ten operator flows and ten spatial questions (rotations, mirror images and cube nets), mixed, in 18 minutes. That's 54 seconds a question.
For flows, work out each operator from the examples before you touch the question, and write the rules down. For rotations, find one asymmetric feature and track it. For nets, pick a face, fold its neighbors around it in your head, and check which faces end up opposite.