Yea, really old thread....
I did similar calculations about a year ago for my tractor. I checked with different setups combinations of tractor, FEL, and bushhog.
The static point is higher than alot of people think, but there is something important that was missed 13 years ago. Not only do you need to know the COG height, but you need to ALSO know its fore/aft location. The closer to the rear, the higher the tipping angle. The closer to the front, the less the tipping angle since the front is on a pivot.
To find COG fore and aft, its simply measuring the F/R weights and using that ratio against the wheel base.
To find the exact height requires a way to lift one end of the tractor a specified distance and having the ability to weigh the tractor with one end elevated. (usually 24", but the higher, the greater accuracy). Then there is a formula that factors the weight transfer. Obviously the higher COG will transfer more weight when one end is raised.