For tidal energy, the stronger current is found closer to the surface. It is not necessary and even not desirable to install machines in deep water.
For AWE the issue is reversed, since one of the purposes is harnessing high altitude winds. That said “The Pyramid” ratio (which is closer to Minesto’s ratio) seems preferable to me: Unlock the market by shortening the tether. The main thing is to be able to increase the dimensions of the wing or wing arrays when the tether lengthens. But it may not be the priority yet.