there is a short video from (Master)Coach David Cameron
about the HEC, where he demonstrates the TI-point of view.
Last but not least we should think more about Terry's: Don't move water around, move your body forward. A good/ergonomic lever will be helpful, as much drag as possible will be helpful too, but if both are just used to move water around in vortex and whirl, we're simply "wasting" energy. So the miracle of the individual best catch and press (I think) will be that one, where we will feel the greatest ball of water behind our arm against which we can press ourself forward without disturbing the ball/water or only in least manner. And we can only achieve that with the simple - or better the much more difficult thing: We have to find the very best feeling for the water
to become able to do so.