Evaluate a "Herodotus Machine"

I wish to Math Review-2.pdf build machines based on the "Herodotus Machine" and I need help with design variables for various sizes (ie. block size, force required to tilt, extended lever length, etc.) The calculations on the first two pages, I believe, are correct for the Force required to tilt from a level and then a tilted position, but I am unsure of some of the page 3 calculations. I am having problems determining the length of the tilt arm for a given Mechanical Advantage. Once I have the procedure down I will put them in a spreadsheet and be able to give customers a machine that meets their specifications. Here is a video of this machine. 

https://www.youtube.com/watch?v=4hLQoD3Cwag

Please consider your desire to work on this. It is not a difficult problem, but I would like for it to be through and complete. I have built several models and they come close to results I calculated, but they are not as exact as I would like them to be.