A polishing head is tested in a test station having a pedestal for supporting a test wafer and a controllable pedestal actuator to move a pedestal central wafer support surface and a test wafer toward the polishing head. In another aspect of the present description, the test wafer may be positioned using a positioner having a first plurality of test wafer engagement members positioned around the pedestal central wafer support surface. In another aspect, the wafer position may have a second plurality of test wafer engagement members positioned around an outer wafer support surface disposed around the pedestal central wafer support surface and adapted to support a test wafer. The second plurality of test wafer engagement members may be distributed about a second circumference of the ring member, the second circumference having a wider diameter than the first circumference. Additional embodiments and aspects are described and claimed.