I asked my buddy for you since he has a massive piece that he frags regularly; sucker has to be at least 4x5 on the extremely conservative side. He uses a set of big bone cutters and looks for ridges (he noticed the ridge on the top left corner of your frag). No eyes needed since they regrow them extremely quickly.
Thanks @Ibn. So he frags the protrusions? Mine is super puffy all the time and almost always have sweepers out. Maybe because it's in mid to high flow. I'll move it to lower flow and see if I can get it to stop puffing up so I can see where the ridges are.
I think @ Enderturtle used a band saw and cut his up between the mouths. So each frag would have at least one mouth. In fact, if I'm not mistaken, @Vhuang168 isnt that where your frag came from?