Paul, Terraces may be a reason to let the wings float. Usually however we find it best on most field surfaces to lock the wings rigid, have gage wheels on the wings and let the 3-point lower links float (lower arms in the slots, etc).

This lets the two toolbar gage wheels, spread apart, define an average line parallel to the ground. Our Pluribus has a lot of vertical travel. This also means you get constant row spacing all the way across. 

Terraces however may be worth letting the wings float. But not all terraces are the same. What some folks (SC KS) call terraces I can hardly see. In other cases (NE KS) some terraces you can hardly stand on.

Our strip is usually about 8 in wide so you can have a bit of a guess row between the wing and center sections and still be on the strip if not centered.

Jim at Dawn