Research was done into the deflection of a totally unsupported (topside) PCB of 0.050" thickness. A dial indicator was placed on the surface and the tooling was set. The deflection ranged from 0.005" to 0.007". This is minor when you consider the tooling will normally be set with a stencil on top of the PCB (for stencil printers)
A high-accuracy force gauge was placed above a pin when the pin was retracted. The gauge was set to record the max force encountered. The average force was 5 gram force (0.18 ounce force). The pins can literally be stopped with a piece of paper at their most sensitive setting. Higher settings can be used to help flatten sagging boards.
However, the most important testing was performed by testing the system out in the field. We hope to be releasing this information shortly, please send me an email and I will release this to you directly.