I hope that's not a big problem, just probed out my old concrete tile on a 40 to add more this spring, and found some was only 18-20 inches deep.
Other places I get to 15 inches too, replaced 35 feet that was all cracked in.
Also got a soil saver for this fall.....
We will see, if it ever rains I guess.
Pretty happy with the soil saver, the chisel plow didnt do much, this thing did something.
The plow seems more dangerous to the tile, drving in the furrow you are 8 inches closer to the tile, with a lot of pull and weight.
I suppose that's why you are interested in an on land hitch.
The soil saver is pretty good, need to chop or disk stalks still, but it was worlds better than the old little chisel, that plugged up easy in chopped stalks....