Below the basic computation I used. As I am not sure if / how I can convert that into a clean document, I preferred to attach screen copies of the notes I took, hopefully you will find that useful.

I attached the excel file I used to test the computation before implementing it and draw a schematic view of a leg.

The below determines the COG location desired before a given leg can be lifted. 

Also below the excel file I used to draw the COG position based on this mdel.