I actually meant that the spring clamps(not sure what they are called) are placed along the center edges of the tiles so there is not more pressure toward one end of the penis shaft or the other. The only time I had trouble/injury was when the spring clamp slid a little up tile closer toward glans and pressure was distributed unevenly. It does however seem to be more fragile directly under the glans and so I try to leave some space below the glans, the base is plenty tough. This all depends on your actual method/design as some people use screw down vices in each of the four corners as opposed to the original idea of 2 spring clamps on either side of two tiles. Also worth noting that, given the different pressures exerted by the spring clamps people use and thickness of tile(have seen video game cartridge used), there is a lot of variation in the pressures people are applying.
Start: 7/1/14 BPEL 7.25" MEG 4.75"
Current: 10/1/14 BPEL8.2" MEG 5.5" BEG 6" Corona 5.25" EQ=9