How to Be Efficient ????? This is precisely what WC or NS is all about..... It has to do with control of COM, "Center of Mass Movement."..... ie: When you learn, through handle control, to be pulled through COM, you eliminate being pulled through the arms, shoulders, and back. Thus the boat does the work for you, making you more EFFICIENT !!!
 When you learn not only to lean, but to lean in the direction of travel, you accelerate better, thus being more EFFICIENT !!!
Also, Speed not only generates Angle, but it generates Angle with LESS LOAD, thus being more EFFICIENT !!!
For me this form of skiing did away with Back Pain, by being pulled through the COM..... It did away with OTF's, by being more solid through the wakes, leading with the COM and not the shoulders...I only hope some of the misconceptions concerning massive compression and angulation can be dispelled.
Best Regards, ED