Moving the ball up to the next set of holes on the shank will not affect how many links you use.  That just moves the whole assembly up and levels the trailer.
If I were you, I would move the hitch up on the shank one set of holes if that will level the trailer.
While you have the hitch head apart doing the above, put another washer or two on the pin behind the head which will tilt it down a bit more to start.  Then you can use 6 links again which will make the bars parallel to the frame and still give you the WD you need to put a bit more weight on the front axle of the truck.
Barney