Noting that the Fleks3d plate is thinner than the stock glass plate, and provided with the package are a pair of big clunky clips that interfere with print-head movement and build space, I've decided to draw the adequate ergonomic design for the task. A trio in triangular formation as seen in the attached image seems to do the job for me. A pair alone would also work but the central one is more of an extra safety measure in order to minimize lateral dislocation.