I agree that the short side radius is bad, which will (probably) be helped by a curved floor. If a lump was made in symmetrical (L&R) pairs they would look like an upside down "L". Each could be rotated 90° and inserted, then locked together.
However: there's no existing head bolt to attach either one. I don't see any easy method here?
Any insertion also decreases port area somewhat, so this may work best on the large port heads such as the H.
