I think you two might be talking about two different kinds of porpoising! What Fastback is describing for a tail heavy plane is more from over sensitivity in the controls, which in turn causes some over correction with the sticks and will occur at a lower speed as well as at faster speeds. This will sometimes smooth out briefly during acceleration.
The porpoising from a nose heavy plane is smoother and more predictable and does require faster landing speed to overcome. Just my 2 cents