Some pictures of the testing:
This was the worst compression failure, that occurred at ~163.5 pounds pressure. This piece was tested with this damage on the underside for the rest of the testing, and it seemed to have minimal affect on the deflection, if any.
The lighter fabrics started to show some compression damaged at position #3 with ~46.5 pounds of pressure, and most showed a compression dent in position #2 with 77.5 pounds pressure. All samples had a compression dent after testing in position #1 with 116.5 pounds pressure. When possible, the (largest) dent was on the underside on tests after a sample was damaged. This may have exacerbated the deflection in those later tests, but it seemed to be minimal and not change the general pattern of the data.