Umm... I have a different manufacturer's version of that block as my mainsheet tackle's lower end... and there's no way I could use it at the upper end, since the boom is over six feet above the cockpit floor, and I'm 5' 4"..
Six foot or so here, but it's end-boom sheeting, and the binnacle's in a "cockpit well": if you want to cleat off the sheet, you step out of the well.
Interestingly, my wife is five foot tall, and I rigged it that way so she could sheet in by pulling down like it was a halyard, rather than by pulling up by bracing her legs. You cleat by holding your arms up at the end of the pull.
I'll try to get a picture. It's not as weird as it sounds.