If I read Ricky's reply correct Keefer, he actually has the eccentic hub set so that it gives the shortest wheelbase possible!!!
I used to have my old 748 set with the hub at 3.00 (longest wheelbase possible) and the steering head to fast. I rode it like this for ages, and also set the ride height with the Ducati tool as suggested. Handled sweet and was very stable.
Now I have a 916SP and have the same hub position, same ride height, but now the head setting on normal, as it has mag wheels, I feel this kinda compensates for the steep steering head angle.
I am amazed you where able to ride your 748 on the settings you mention...I'm not suprised it feels dangerous...goes against a lot of whats often said regarding setting up a Duke...but if it works for you (or used to!!
)