I run 245/70 R 16 BFG AT's on my 94 300 Tdi, I run them at 27psi in the front, 35psi in the rear at all times except when towing, when i raise the rear to 40psi.
Any more pressure in the front results in a lot of feedback through the steering wheel, any more in the rear when not towing results in her becoming a little tail happy.
I drive my Disco hard on the road, and these settings work for me. Well impressed with the tyres too, had Goodyear ATR's before (235/70 R 16) which I liked, but the Goodrich's are a definite improvment, and after a year and 14000 miles still look like new.
There,
My 2 pence's worth, hope its some help to someone!