I'm just at the stage of setting up the heads to the home position. I have setup the IR sensor and managed to pull the centre glass plate clip off with the heads (dual) as the heads move to the home position. So Y end stop needs adjusting. What would be good would be an overview of the homing procedure rather than a series of steps where some instructions are given for the Pro and Lite (Single), then some for Dual etc. which is a lot of scrolling and losing your place of where in the calibration process you are. An overview of one liners, and a basic knowledge of menu commands would (for me) be a lot simpler than scrolling through a lot of images and brief instructions on what command to issue. Also it is impossible to see where on the grid the head is to see if you are at the home position.
A simple "offset" system would work well, like a flat strip of fixed length that attaches to (around) a nozzle. As the bed is graduated in cm then say 10cm strip would be on the 10 cm grid line when the nozzle was actually at zero. No poking around with a torch trying to see where the nozzle was at an angle that means there is a significant parallax error.
Actually - that idea spurs me on to maybe get it all spot on at some point. A combination of using a pin (hopefully straight) along with some offset GCODE movements would let you nail this pretty preceisely.