Well im not sure how this one would work as it not on the tractor so we havent any way to tell the angle of the shovel face. If it steep then it should go down to china, but if its flattened out some then the depth would be limited to how much suck it has.
I never did like these type of digger as if you have grassy potatos, then the stuff want to wrap up on the shank and your forever having to stop and clean it off. I used to have a horse drawn IH digger, where you have a diamond shaped blade and supports on both sides that let the crop go down the middle and out the back. never had a plugging problem with it. Been looking at building something in a garden tractor scale that would work similar, but this work takes a lot more power and traction than most two wheeled tractors will give you.